NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 11
Chapter Name Circles
Exercise Ex 11.6
Number of Questions Solved 10
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6

Question 1.
Prove that the line of centres of two intersecting circles subtends equal angles at the two points of intersection.
Solution:
Given: Two circles with centres O and O’ which intersect each other at C and D.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 1
To prove: ∠OCO’ = ∠ODO’
Construction: Join OC, OD, O’C and O’D
Proof: In ∆ OCO’and ∆ODO’, we have
OC = OD (Radii of the same circle)
O’C = O’D (Radii of the same circle)
OO’ = OO’ (Common)
∴ By SSS criterion, we get
∆ OCO’ ≅ ∆ ODO’
Hence, ∠OCO’ = ∠ODO’ (By CPCT)

Question 2.
Two chords AB and CD of lengths 5 cm and 11 cm, respectively of a circle are parallel to each other and are on opposite sides of its centre. If the distance between AB and CD is 6 cm, find the radius of the circle.
Solution:
Let O be the centre of the given circle and let its radius be cm.
Draw ON ⊥ AB and OM⊥ CD since, ON ⊥ AB, OM ⊥ CD and AB || CD, therefore points N, O, M are collinear.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 2
Let ON = a cm
∴ OM = (6 – a) cm
Join OA and OC.
Then, OA = OC = b c m
Since, the perpendicular from the centre to a chord of the circle bisects the chord.
Therefore, AN = NB= 2.5 cm and OM = MD = 5.5 cm
In ∆OAN and ∆OCM, we get
OA2 = ON2 + AN2
OC2 = OM2 + CM2
⇒ b2 = a2 + (2.5)2
and, b2 = (6-a)2 + (5.5)2 …(i)
So, a2 + (2.5)2 = (6 – a)2 + (5.5)2
⇒ a2 + 6.25= 36-12a + a2 + 30.25
⇒ 12a = 60
⇒ a = 5
On putting a = 5 in Eq. (i), we get
b2 = (5)2 + (2.5)2
= 25 + 6.25 = 31.25
So, r = \( \sqrt{31.25} \) = 5.6cm (Approx.)

Question 3.
The lengths of two parallel chords of a circle are 6 cm and 8 cm. If the smaller chord is at distance 4 cm from the centre, what is the distance of the other chord from the centre ?
Solution:
Let PQ and RS be two parallel chords of a circle with centre O such that PQ = 6 cm and RS = 8 cm.
Let a be the radius of circle.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 3
Draw ON ⊥ RS, OM ⊥ PQ. Since, PQ || RS and ON ⊥ RS, OM⊥ PQ, therefore points 0,N,M are collinear.
∵ OM = 4 cm and M and N are the mid-points of PQ and RS respectively.
PM = MQ = \(\frac { 1 }{ 2 }\) PQ = \(\frac { 6 }{ 2 }\) = 3 cm
and RN = NS = \(\frac { 1 }{ 2 }\) RS = \(\frac { 8 }{ 2 }\) = 4 cm
In ∆OPM, we have
OP2 = OM2 + PM2
⇒ a2 =42 + 32 = 16 + 9 = 25
⇒ a = 5
In ∆ORN, we have
⇒ OR2 = ON2 + RN2
⇒ a2 = ON2 + (4)2
⇒ 25 = ON2 + 16
⇒ ON2 = 9
⇒ ON = 3cm
Hence, the distance of the chord PS from the centre is 3 cm.

Question 4.
Let the vertex of an angle ABC be located outside a circle and let the sides of the angle intersect equal chords AD and CE with the circle. Prove that ∠ABC is equal to half the difference of the angles subtended by the chords AC and DE at the centre.
Solution:
Since, an exterior angle of a triangle is equal to the sum of the interior opposite angles.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 4
∴ In ∆BDC, we get
∠ADC = ∠DBC + ∠DCB …(i)
Since, angle at the centre is twice at a point on the remaining part of circle.
∴ ∠DCE = \(\frac { 1 }{ 2 }\) ∠DOE
⇒ ∠DCB = \(\frac { 1 }{ 2 }\) ∠DOE (∵ ∠DCE = ∠DCB)
∠ADC = \(\frac { 1 }{ 2 }\) ∠AOC
∴ \(\frac { 1 }{ 2 }\) ∠AOC = ∠ABC + \(\frac { 1 }{ 2 }\) ∠DOE (∵ ∠DBC = ∠ABC)
∴ ∠ABC = \(\frac { 1 }{ 2 }\) (∠AOC – ∠DOE)
Hence, ∠ABC is equal to half the difference of angles subtended by the chords AC and DE at the centre.

Question 5.
Prove that the circle drawn with any side of a rhombus as diameter, passes through the point of intersection of its diagonals.
Solution:
Given: PQRS is a rhombus. PR and SQ are its two diagonals which bisect each other at right angles.
To prove: A circle drawn on PQ as diameter will pass through O.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 5
Construction: Through O, draw MN || PS and EF || PQ.
Proof : ∵ PQ = SR ⇒ \(\frac { 1 }{ 2 }\) PQ = \(\frac { 1 }{ 2 }\) SR
So, PN = SM
Similarly, PE = ON
So, PN = ON = NQ
Therefore, a circle drawn with N as centre and radius PN passes through P, O, Q.

Question 6.
ABCD is a parallelogram. The circle through A, B and C intersect CD (produced if necessary) at E. Prove that AE = AD.
Solution:
Since, ABCE is a cyclic quadrilateral, therefore
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 6
∠AED+ ∠ABC= 180°
(∵ Sum of opposite angle of a cyclic quadrilateral is 180°) .. .(i)
∵ ∠ADE + ∠ADC = 180° (EDC is a straight line)
So, ∠ADE + ∠ABC = 180°
(∵ ∠ADC = ∠ABC opposite angle of a || gm).. .(ii)
From Eqs. (i) and (ii), we get
∠AED + ∠ABC = ∠ADE + ∠ABC
⇒ ∠AED = ∠ADE
∴ In ∆AED We have
∠AED = ∠ADE
So, AD = AE
(∵ Sides opposite to equal angles of a triangle are equal)

Question 7.
AC and BD are chords of a circle which bisect each other. Prove that
(i) AC and BD are diameters,
(ii) ABCD is a rectangle.
Solution:
(i) Let BD and AC be two chords of a circle bisect at P.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 7
In ∆APB and ∆CPD, we get
PA = PC ( ∵ P is the mid-point of AC)
∠APB = ∠CPD (Vertically opposite angles)
and PB = PD (∵ P is the mid-point of BD)
∴ By SAS criterion
∆CPD ≅ ∆APB
∴ CD= AB (By CPCT) …(i)
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 8
∴ BD divides the circle into two equal parts. So, BD is a diameter.
Similarly, AC is a diameter.
(ii) Now, BD and AC bisect each other.
So, ABCD is a parallelogram.
Also, AC = BD
∴ ABCD is a rectangle.

Question 8.
Bisectors of angles A, B and C of a ∆ABC intersect its circumcircle at D, E and F, respectively. Prove that the angles of the ∆DEF are 90° – \(\frac { 1 }{ 2 }\) A, 90° – \(\frac { 1 }{ 2 }\) B and 90° – \(\frac { 1 }{ 2 }\) C.
Solution:
∵ ∠EDF = ∠EDA + ∠ADF
∵ ∠EDA and ∠EBA are the angles in the same segment of the circle.
∴ ∠EDA = ∠EBA
and similarly ∠ADF and ∠FCA are the angles in the same segment and hence
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 9

Question 9.
Two congruent circles intersect each other at points A and B. Through A any line segment PAQ is drawn so that P, Q lie on the two circles. Prove that BP = BQ.
Solution:
Let O’ and O be the centres of two congruent circles.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 10
Since, AB is a common chord of these circles.
∴ ∠BPA = ∠BQA
(∵ Angle subtended by equal chords are equal)
⇒ BP = BQ

Question 10.
In any ∆ ABC, if the angle bisector of ∠A and perpendicular bisector of BC intersect, prove that they intersect on the circumcircle of the ∆ABC.
Solution:
(i) Let bisector of ∠A meet the circumcircle of ∆ABC at M.
Join BM and CM.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 11
∴ ∠MBC = ∠MAC (Angles in same segment)
and ∠BCM = ∠BAM (Angles in same segment)
But ∠BAM = ∠CAM (∵ AM is bisector of ∠A)…. .(i)
∴ ∠MBC = ∠BCM
So, MB = MC (Sides opposite to equal angles are equal)
So, M must lie on the perpendicular bisector of BC
(ii) Let M be a point on the perpendicular bisector of BC which lies on circumcircle of ∆ ABC.
Join AM.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6 img 12
Since, M lies on perpendicular bisector of BC.
∴ BM = CM
∠MBC = ∠MCB
But ∠MBC = ∠MAC (Angles in same segment)
and ∠MCB = ∠BAM (Angles in same segment)
So, from Eq. (i),
∠BAM = ∠CAM
AM is the bisector of A.
Hence, bisector of ∠A and perpendicular bisector of BC at M which lies on circumcircle of ∆ABC.
We hope the NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6, help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.6, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 11
Chapter Name Circles
Exercise Ex 11.5
Number of Questions Solved 12
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5

Question 1.
In figure A,B and C are three points on a circle with centre 0 such that ∠BOC = 30° and ∠ AOB = 60°. If D is a point on the circle other than the arc ABC, find ∠ ADC.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 1
Solution:
∴ ∠AOC = ∠AOB + ∠BOC = 60P + 30° = 90°
∴ Arc ABC makes 90° at the centre of the circle.
∴ ∠ADC = \(\frac { 1 }{ 2 }\) ∠AOC
(∵ The angle subtended by an arc at the centre is double the angle subtended by it any part of the circle.)
= \(\frac { 1 }{ 2 }\) x 90° = 45°

Question 2.
A chord of a circle is equal to the radius of the circle, find the angle subtended by the chord at a point on the minor arc and also at a point on the major arc.
Solution:
Let BC be chord, which is equal to the radius. Join OB and OC.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 2
Given, BC=OB = OC
∴ ∆OBC is an equilateral triangle.
∠BOC =60°
∴ BAC = \(\frac { 1 }{ 2 }\) ∠BOC
= \(\frac { 1 }{ 2 }\) x 60° = 30°
(∵ The angle subtended by an arc at the centre is double the angle subtended by it any part of the circle.)
Here, ABMC is a cyclic quadrilateral.
∴ ∠BAC + ∠BMC = 180°
(∵ In a cyclic quadrilateral the sum of opposite angles is 180°)
⇒ ∠BMC= 180° – 30° =150°

Question 3.
In figure, ∠PQR = 100°, where P, Q and R are points on a circle with centre O. Find ∠OPR.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 3
Solution:
∴ ∠POR = 2∠PQR = 2 x 100° = 200°
(Since, the angle subtended by the centre is double the angle subtended by circumference.)
Since, in ∆OPR, ∠POR = 360° – 200° = 160° .. (i)
Again, ∆ OPR, OP = OR (Radii of the circle)
∴ ∠OPR = ∠ORP (By property of isosceles triangle)
In ∆POR, ∠OPR + ∠ORP + ∠POR = 180° …(ii)
From Eqs. (i) and (ii), we get
∠OPR + ∠OPR + 160° = 180°
∴ 2 ∠OPR = 180° – 160° = 20°
∴ ∠OPR = \(\frac { { 120 }^{ circ } }{ 2 }\) = 10°

Question 4.
In figure, ∠ABC = 69°,∠ACB = 31°, find ∠BDC.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 4
Solution:
∵ ∠BDC = ∠BAC …(i)
(Since, the angles in the same segment are equal)
Now , in ∆ABC
∴ ∠A + ∠B+ ∠C= 180°
⇒ ∠A+ 69°+ 31° = 180°
⇒ ∠A + 100° = 180°
∴ ∠A = 180° – 100° = 80°
⇒ ∠BAC=80°
∴ From Eq.(i)∠BDC = 80°

Question 5.
In figure, A, B and C are four points on a circle. AC and BD intersect at a point E such that ∠ BEC = 130° and ∠ ECD = 20°. Find ∠BAC.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 5
Solution:
∴ ∠AEB = 180° – 130° = 50° (Linear Pair) …(i)
⇒ ∠CED = ∠AEB = 50° (Vertically opposite)
Again ∠ABD = ∠ACD (Since, the angles in the same segment are equal)
∠ABE = ∠ECD
⇒ ∠ABE = 180° …(ii)
∴ In ∆ CDE
∠A+ 20° + 50° = 180° [From Eqs. (i) and (ii)]
∠A + 70° = 180°
∴ ∠A = 180°- 70° =110°
Hence ∠BAC = 110°

Question 6.
ABCD is a cyclic quadrilateral whose diagonals intersect at a point E. If ∠DBC = 70°, ∠BAC is 30°, find ∠BCD. Further, if AB = BC, find ∠ECD.
Solution:
Angles in the same segment are equal.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 6
∴ ∠BDC = ∠BAC
∴ ∠BDC = 30°
In ∆ BCD, we have
∴ ∠BDC + ∠DBC + ∠BCD = 180° (Given, ∠DBC = 70° and ∠BDC = 30°)
∴ 30° + 70° + ∠BCD = 180°
∴ ∠BCD= 180°-30°-70° = 80°
If AB = BC, then ∠BCA = ∠BAC= 80° (Angles opposite to equal sides in a triangle are equal)
Now, ∠ECD = ∠BCD – ∠BCA = 80° – 30P = 50° (∵ ∠BCD = 80° and ∠BCA =30°)
Hence, ∠BCD = 80°
and ∠ECD = 50°

Question 7.
If diagonals of a cyclic quadrilateral are diameters of the circle through the vertices of the quadrilateral, prove that it is a rectangle.
Solution:
Given: Diagonals NP and QM of a cyclic quadrilateral are diameters of the circle through the vertices M, P, Q and N of the quadrilateral NQPM.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 7
To prove: Quadrilateral NQPM is a rectangle.
Proof: ∵ ON = OP = OQ = OM (Radii of circle)
Now, ON = OP = \(\frac { 1 }{ 2 }\) NP
and OM = OQ = \(\frac { 1 }{ 2 }\) MQ
∴ NP = MQ
Hence, the diagonals of the quadrilateral MPQN are equal and bisect each other. So, quadrilateral NQPM is a rectangle.

Question 8.
If the non-parallel sides of a trapezium are equal, prove that it is cyclic.
Solution:
Given: Non-parallel sides PS and QR of a trapezium PQRS are equal.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 8
To prove: ABCD is a cyclic trapezium.
Construction: Draw SM ⊥ PQ and RN ⊥ PQ.
Proof In ∆SMP and ∆RNQ, we get
SP = RQ (Given)
∠SMP = ∠RNQ (Each = 90°)
and SM = RN
(∵ Distance between two parallel lines is always equal)
∴ By RHS criterion, we get
∆ SMP ≅ ∆ RNQ
So, ∠P = ∠Q (By CPCT)
and ∠PSM = ∠QRN
Now, ∠PSM = ∠QRN
∴ 90° + ∠PSM = 90° + ∠QRN (Adding both sides 90°)
∴ ∠MSR + ∠PSM = ∠NRS + ∠QRN (∵∠MSR = ∠NRS = 90°)
So, ∠PSR = ∠QRS
i.e., ∠S = ∠R
Thus, ∠P = ∠Q and ∠R = ∠S …(i)
∴ ∠P+ ∠Q+ ∠R+ ∠S = 360° (∵ Sum of the angles of a quadrilateral is 360°)
∴ 2∠S + ∠Q = 360° [From Eq. (i)]
∠S+∠O = 180°
Hence, PQRS is a cyclic trape∠ium.

Question 9.
Two circles intersect at two points B and C. Through B, two line segments ABD and PBQ are drawn to intersect the circles at A,D and P, Q respectively (see figure). Prove that ∠ ACP = ∠QCD.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 9
Solution:
Given: Two circles intersect at two points B and C. Through B two line segments ABD and PBQ are drawn to intersect the circles at A, D and P, Q, respectively.
To prove: ∠ACP = ∠QCD
Proof: In circle I, ∠ACP = ∠ABP (Angles in the same segment) …(i)
In circle II, ∠QCD = ∠QBD{Angles in the same segment)…(ii)
∠ABP = ∠QBD (Vertically opposite angles)
From Eqs. (i) and (ii), we get ∠ACP = ∠QCD

Question 10.
If circles are drawn taking two sides of a triangle as diameters, prove that the point of intersection of these circles lie on the third side.
Solution:
Given: Two circles are drawn with sides AC and AB of AABC as diameters . Both circles intersect each other at D.
To prove: D lies on BC.
Construction: Join AD.
Proof: Since, AC and AB are the diameters of the two circles.
∠ADB = 90° ( ∴ Angles in a semi-circle) …(i)
and ∠ADC = 90° (Angles in a semi-circle) …(ii)
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 10
On adding Eqs. (i) and (ii), we get
∠ADB + ∠ADC = 90° + 90° = 180°
Hence, BCD is a straight line.
So, D lies on BC.

Question 11.
ABC and ADC are two right angled triangles with common hypotenuse AC. Prove that ∠CAD = ∠CBD.
Solution:
Since, ∆ADC and ∆ABC are right angled triangles with common hypotenuse.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 11
Draw a circle with AC as diameter passing through B and D. Join BD.
∵ Angles in the same segment are equal.
∴ ∠CBD = ∠CAD

Question 12.
Prove that a cyclic parallelogram is a rectangle.
Solution:
Given: PQRS is a parallelogram inscribed in a circle.
To prove: PQRS is a rectangle.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5 img 12
Proof: Since, PQRS is a cyclic quadrilateral.
∴ ∠P+∠R = 180°
(∵ Sum of opposite angles in a cyclic quadrilateral is 180°) …(i)
But ∠P = ∠R (∵ In a || gm opposite angles are equal) …(ii)
From Eqs. (i) and (ii), we get
∠P = ∠R = 90°
Similarly, ∠Q = ∠S = 90
∴ Each angle of PQRS is 90°.
Hence, PQRS is a rectangle.
We hope the NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5, help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.5, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 11
Chapter Name Circles
Exercise Ex 11.4
Number of Questions Solved 6
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4

Question 1.
Two circles of radii 5 cm and 3 cm intersect at two points and the distance between their centres is 4 cm. Find the length of the common chord.
Solution:
Let O and O’ be the centres of the circles of radii 5 cm and 3 cm, respectively.
Let AB be their common chord.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 1
Given, OA = 5 cm, O’A = 3cm and OO’ = 4 cm
∴ AO’2 + OO’2 = 32 + 42 = 9 + 16- 25 = OA2
∴ OO’A is a right angled triangle and right angled at O’
Area of ∆OO’A = \(\frac { 1 }{ 2 }\) x O’A x OO’
= \(\frac { 1 }{ 2 }\) x 3x 4= 6sq units …(i)
Also, area of ∆OO’A = \(\frac { 1 }{ 2 }\) x OO’ x AM
= \(\frac { 1 }{ 2 }\) x 4 x AM =2 AM …(ii)
From Eqs. (i) and (ii), we get
2AM = 6 ⇒ AM = 3
Since, when two circles intersect at two points, then their centre lie on the perpendicular bisector of the common chord.
∴ AB = 2 x AM= 2 x 3 = 6 cm

Question 2.
If two equal chords of a circle intersect within the circle, prove that the segments of one chord are equal to corresponding segments of the other chord.
Solution:
Given: MN and AS are two chords of a circle with centre O, AS and MN intersect at P and MN = AB
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 2
To prove: MP = PB and PN = AP
Construction: Draw OD ⊥ MN and OC ⊥ AB.
Join OP
Proof : ∵ DM = DN = \(\frac { 1 }{ 2 }\) MN (Perpendicular from centre bisects the chord)
and AC = CB = \(\frac { 1 }{ 2 }\) AB (Perpendicular from centre bisects the chord)
MD = BC and DN = AC (∵ MN = AS)…(i)
in ∆ODP and ∆OPC
OD = OC (Equal chords of a circle are equidistant from the centre)
∠ ODP = ∠OCP
OP = OP (Common)
∴ RHS criterion of congruence,
∆ ODP ≅ ∆ OCP
∴ DP = PC (By CPCT)…(ii)
On adding Eqs. (i) and (ii), we get
MD + DP = BC + PC
MP = PB
On subtracting Eq. (ii) from Eq. (i), we get
DN – DP = AC – PC
PN = AP
Hence, MP = PB and PN = AP are proved.

Question 3.
If two equal chords of a circle intersect within the circle, prove that the line joining the point of intersection to the centre makes equal angles with the chords.
Solution:
Given: RQ and MN are chords of a with centre O. MN and RQ intersect at P and MN = RQ
To prove: ∠ OPC = ∠ OPB
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 3
Construction: Draw OC ⊥ RQ and OB ⊥ MN.
Join OP.
Proof: In ∆ OCP and ∆ OBP, we get
∠ OCP = ∠ OBP (Each = 90°)
OP = OP (Common)
OC = OB (Equal chords of a circle are equidistant from the centre)
∴ By RHS criterion of congruence, we get
∆ OCP ≅ ∆ OBP
∴ ∠ OPC = ∠ OPB (By CPCT)

Question 4.
If a line intersects two concentric circles (circles with the same centre) with centre 0 at A, B, C and D, prove that AB = CD (see figure).
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 4
Solution:
Let OP be the perpendicular from O on line l. Since, the perpendicular from the centre of a circle to a chord
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 5
Now, BC is the chord of the smaller circle and OP ⊥ BC.
∴ BP = PC ……(i)
Since, AD is a chord of the larger circle and OP ⊥ AD.
∴ AP = PD …(ii)
On subtracting Eq. (i) from Eq. (ii), we get
AP – BP = PD – PC
⇒ AB = CD
Hence proved.

Question 5.
Three girls Reshma, Salma and Mandip are playing a game by standing on a circle of radius 5m drawn in a park. Reshma throws a ball to Salma, Salma to Mandip, Mandip to Reshma. If the distance between Reshma and Salma and between Salma and Mandip is 6 m each, what is the distance between Reshma and Mandip?
Solution:
Let O be the centre of the circle and Reshma, Salma and Mandip are represented by the points Ft, S and M, respectively.
Let RP = xm.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 6
From Eqs. (i) and (ii), we get
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 7
Hence, the distance between Reshma and Mandip is 9.6 m.

Question 6.
A circular park of radius 20 m is situated in a colony. Three boys Ankur, Syed and David are sitting at equal distance on its boundary each having a toy telephone in his hands to talk each other. Find the length of the string of each phone.
Solution:
Let Ankur, Syed and David standing on the point P, Q and R.
Let PQ = QR = PR = x
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 8
Therefore, ∆ PQR is an equilateral triangle. Drawn altitudes PC, QD and RN from vertices to the sides of a triangle and intersect these altitudes at the centre of a circle M.
As PQR is an equilateral, therefore these altitudes bisects their sides.
In ∆ PQC,
PQ2 = PC2 + QC2 (By Pythagoras theorem)
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 9
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4 img 10

We hope the NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4, help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.4, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 11
Chapter Name Circles
Exercise Ex 11.3
Number of Questions Solved 3
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3

Question 1.
Draw different pairs of circles. How many points does each pair have in common? What is the maximum number of common points?
Solution:
Different pairs of circles are
(i) Two points common
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 1
(ii) One point is common
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 2
(iii) No point is common
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 3
(iv) No point is common
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 4
(v) One point is common
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 5
From figures, it is obvious that these pairs many have 0 or 1 or 2 points in common.
Hence, a pair of circles cannot intersect each other at more than two points.

Question 2.
Suppose you are given a circle. Give a construction to find its centre.
Solution:
Steps of construction
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 6
Taking three points P,Q and R on the circle.
Join PQ and QR,
Draw MQ and NS, respectively the perpendicular bisectors of PQ and RQ, which intersect each other at O.
Hence, O is the centre of the circle.

Question 3.
If two circles intersect at two points, prove that their centres lie on the perpendicular bisector of the common chord.
Solution:
Given: Two circles with centres O and O’ intersect at two points M and N so that MN is the common chord of the two circles and OO’ is the line segment joining the centres of the two circles. Let OO’ intersect MN at P.
To prove: OO’ is the perpendicular bisector of MN.
NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3 img 7
Construction: Draw line segments OM, ON, O’M and O’N.
Proof In ∆ OMO’ and ONO’, we get
OM = ON (Radii of the same circle)
O’M = O’N (Radii of the same circle)
OO’ = OO’ (Common)
∴ By SSS criterion, we get
∆ OMO’ ≅ ONO’
So, ∠ MOO’ = ∠ N00′ (By CPCT)
∴ ∠ MOP = ∠ NOP …(i)
(∵ ∠ MOO’ = ∠ MOP and ∠ NOO’ = ∠ NOP)
In ∆ MOP and ∆ NOP, we get
OM = ON (Radii of the same circle)
∠ MOP = ∠NOP [ From Eq(i)]
and OM = OM (Common)
∴ By SAS criterion, we get
∆ MOP ≅ ∆NOP
So, MP = NP (By CPCT)
and ∠ MPO = ∠ NPO
But ∠ MPO + ∠NPO = 180° ( ∵MPN is a straight line)
∴ 2 ∠ MPO = 180° ( ∵ ∠ MPO = ∠ NPO)
⇒ ∠ MPO = 90°
So, MP = PN
and ∠ MPO = ∠ NPO = 90°
Hence, OO’ is the perpendicular bisector of MN.

We hope the NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3, help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 11 Circles Ex 11.3, drop a comment below and we will get back to you at the earliest.

CBSE Sample Papers for Class 9 Maths Paper 3

CBSE Sample Papers for Class 9 Maths Paper 3 is part of CBSE Sample Papers for Class 9 Maths . Here we have given CBSE Sample Papers for Class 9 Maths Paper 3

CBSE Sample Papers for Class 9 Maths Paper 3

Board CBSE
Class IX
Subject Maths
Sample Paper Set Paper 3
Category CBSE Sample Papers

Students who are going to appear for CBSE Class 9 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 3 of Solved CBSE Sample Papers for Class 9 Maths is given below with free PDF download solutions.

Time: 3 Hours
Maximum Marks: 80

General Instructions:

  • All questions are compulsory.
  • Questions 1-6 in Section-A are Very Short Answer Type Questions carrying 1 mark each.
  • Questions 7-12 in Section-B are Short Answer (SA-I) Type Questions carrying 2 marks each.
  • Questions 13-22 in Section-C are Short Answer (SA-II) Type Questions carrying 3 marks each.
  • Questions 23 -30 in Section-D are Long Answer Type Questions carrying 4 marks each.

SECTION-A

Question 1.
Write a rational number between √2 and √3

Question 2.
Find the remainder when P(x) = x3 – 3x2 + 4x + 32 is divided by (x + 2).

Question 3.
What is the equation of y-axis?

Question 4.
If 3∠A = 4∠B = 6∠C, then ∠A : ∠B : ∠C = ?

Question 5.
In which quadrant point (x, y) lies if x < 0, y > 0?

Question 6.
The radii of two cylinders are in the ratio of 2:3 and their heights are in the ratio of 5:3, then find the ratio of their volumes.

SECTION-B

Question 7.
Factorize: x(x – y)3 + 3x2y (x -y).

Question 8.
The base of an Isosceles triangle measure 24 cm and its area is 192 cm². Find its perimeter.

Question 9.
The runs scored by two batsmen in a cricket match is 164. Write a linear equation in two variables x and y. Also write a solution of this equation.

Question 10.
12 packets of salts, each marked 2 kg, actually contained the following weights (in kg) of salt.
1.950, 2.020, 2.060, 1.980, 2.030, 1.970
2.040, 1.990, 1.985, 2.025, 2.000, 1.980
Out of these packets one packet is chosen at random. What is the probability that the chosen packet contains more than 2 kg of salt?

Question 11.
The percentage of marks obtained by a student in six unit test are given below.
CBSE Sample Papers for Class 9 Maths Paper 3 11
The unit test is selected at random. What is the probability that the student gets more than 60% marks in the test?

Question 12.
Evaluate (104)3 using suitable identity.

SECTION-C

Question 13.
If x = 7 + 4√3 , then find the value of \(\left( \sqrt { x } +\frac { 1 }{ \sqrt { x } } \right) \)
OR
Find the value of √4.3 geometrically and represent √4.3 on a given real line.

Question 14.
a3 – b3 + 1 + 3ab

Question 15.
In the figure, AB || CD. Prove that ∠p + ∠q – ∠r = 180°.

Question 16.
In the given figure, ABC is a triangle in which AB = AC. Side BA is produced to D, such that AB = AD. Prove that ∠BCD = 90°.

Question 17.
Mid Point Theorem: Prove that the line segment joining the midpoints of any two sides of a triangle is parallel to the third side and equal to half of it.
OR
Prove that parallelograms on the same base and between same parallels are equal in area.

Question 18.
In the given figure O is the centre of circle, prove that ∠x + ∠y = ∠z
CBSE Sample Papers for Class 9 Maths Paper 3 18

Question 19.
Construct a ∆ABC in which BC = 6 cm, ∠B = 60° and sum of other two sides is 9 cm [i.e., AB + AC = 9 cm].

Question 20.
Plot the points A(3, 3), B(2, 4), C(5, 5), D(0, 2), E(3, -3) and F(-5, -5) on a graph paper. Which of these points are the mirror images in
(i) x-axis,
(ii) y-axis?

Question 21.
A cylindrical metallic pipe is 14 cm long. The difference between the outside and inside surface is 44 cm². If the pipe is made up of 99 cubic cm of metal, find the outer and inner radii of the pipe.

Question 22.
The total surface area of a solid cylinder is 231 cm² and its curved surface area is \(\frac { 2 }{ 3 }\) of the total surface area. Find the volume of the cylinder.

SECTION-D

Question 23.
Express \(0.6+0.\overline { 7 } +0.\overline { 47 } \) in the form \(\frac { p }{ q }\), wherep and q are integers and q ≠ 0.

Question 24.
If both (x – 2) and \(x-\frac { 1 }{ 2 }\) are factors of polynomial Px² + 5x + r show that \(\frac { P }{ r }\) = 1.

Question 25.
A pharmacist needs to strengthen a 15% alcoholic solution to one of 32% alcohol. How much pure alcohol should be added to 800 ml of 15% solution?

Question 26.
In the figure, POQ is a line, Ray OR is perpendicular to line PQ, OS is another ray lying between rays OP and OR. Prove that
∠ROS = \(\frac { 1 }{ 2 }\)(∠QOS – ∠POS)

Question 27.
In the given figure, C is the mid point of AB. If ∠DCA = ∠ECB and ∠DBC = ∠EAC, prove that
(i) ∆DBC ≅ ∆EAC
(ii) DC = EC

Question 28.
In the adjoining figure, D, E, F are mid points of the sides BC, CA and AB of ∆ABC. If BE and DF intersect at X while CF and DE intersect at Y, prove that XY = \(\frac { 1 }{ 4 }\)BC

Question 29.
Draw a histogram to represent the following frequency distribution:
CBSE Sample Papers for Class 9 Maths Paper 3 29

Question 30.
Kartikeya wanted to make a temporary shelter for street dogs by making a box like structure with tarpaulin that covers all the four sides and the top of the house. How much tarpaulin would be referred to make the shelter of height 2.5 m with base dimensions 4m x 3m. Assuming stitching margin is negligible. Which values are depicted in this question?

Solutions

Solution 1.
√2 = 1.414, √3 = 1.732
Rational number between √2 and √3 = \(\frac { \sqrt { 2 } +\sqrt { 3 } }{ 2 } \) = 1.573 ~ 1.6 upto one place of decimal = \(\frac { 8 }{ 5 }\)

Solution 2.
P(x) = x3 – 3x2 + 4x + 32,x + 2 = 0 => x = -2
When P(x) is divided by (x + 2), we get
Remainder = P(-2) = [(-2)3 – 3(-2)2 + 4(-2) + 32] = -8 – 12 – 8 + 32 = 4
Remainder = 4

Solution 3.
x = 0.

Solution 4.
Let 3∠A = 4∠B = 6∠C = k°
CBSE Sample Papers for Class 9 Maths Paper 3 4

Solution 5.
If x < 0, y > 0 => x = -ve and y = +ve => P(x, y) lies in quadrant II because it is (-, +).

Solution 6.
Let their radius be 2x cm and 3x cm and their height be 5y cm and 3y cm respectively and volume of cylinder = πr²h
CBSE Sample Papers for Class 9 Maths Paper 3 6

Solution 7.
x(x – y)3 + 3x2y (x – y) = x(x – y) [(x – y)2 + 3xy] = x(x – y) [(x2 + y2 – 2xy + 3xy)]
= x (x – y) (x2 + y2 + xy).

Solution 8.
AL ⊥ BC
CBSE Sample Papers for Class 9 Maths Paper 3 8
Hence perimeter of Isosceles triangle = 20 + 20 + 24 = 64 cm.

Solution 9.
Both Batsmen make runs = x + y = 164
So, linear equation = x + y = 164
If x = 100, then y = 164 – 100 = 64
One solution is
CBSE Sample Papers for Class 9 Maths Paper 3 9

Solution 10.
Total number of packets of salts = 12
Number of packets containing more than 2 kg of salt = 5.
CBSE Sample Papers for Class 9 Maths Paper 3 10

Solution 11.
Number of test in which student gets more than 60% marks = 2.
Total number of test = 6
CBSE Sample Papers for Class 9 Maths Paper 3 11

Solution 12.
(104)3 = (100 + 4)3 = (100)3 + (4)3 + 3(100)(4)(100 + 4)
= 1000000 + 64 + 1200 (100 + 4)
= 1000000 + 64 + 120000 + 4800 = 1124864

Solution 13.
CBSE Sample Papers for Class 9 Maths Paper 3 13
Steps of Construction:
Draw a line segment AB = 4.3 units and extend it to C such that BC = 1 unit.
Find the mid point O of AC.
Draw a semicircle with O as centre and OA as radius.
Draw BD ⊥ AC intersecting the semicircle at D.
Then BD = √4.3 units
with B as centre and BD as radius, draw an arc meeting with AC produced at E. Then BE = BD = √4.3 units.
CBSE Sample Papers for Class 9 Maths Paper 3 13.1

Solution 14.
a3 – b3 + 1 + 3ab = a3 + (-b)3 + 1 + 3ab = a3 + (-b)3 + (1)3 – 3 x a x (-b) x 1
a3 – b3 + 1 + 3ab = (a – b + 1) (a2 + b2 + 1 + ab + b – a)
= (a – b + 1) (a2 + b2 + ab – a + b + 1)
a3 – b3 + 1 + 3 ab = (a – b + 1) (a2 + b2 + ab – a + b + 1)

Solution 15.
CBSE Sample Papers for Class 9 Maths Paper 3 15
AB || CD.
Through F, draw PFQ || AB || CD
So, q = ∠1 + ∠2
AB || PF and EF is transversal line
∠p° + ∠1 = 180° …(i)
Again
PF || CD and GF is transversal line
∠2 = ∠r [Alternate Interior angles] …(ii)
CBSE Sample Papers for Class 9 Maths Paper 3 15.1
Adding (i) and (ii)
∠p + ∠1 + ∠2 = 180° + ∠r
∠p + (∠1 + ∠2) = 180° + ∠r
∠p + ∠q = 180° + ∠r
∠p + ∠q – ∠r = 180°

Solution 16.
CBSE Sample Papers for Class 9 Maths Paper 3 16
AB = AC => ∠ABC = ∠ACB
AC = AD => ∠ADC = ∠ACD
∴ ∠ABC + ∠ADC = ∠ACB + ∠ACD = ∠BCD
∠DBC + ∠BDC = ∠BCD
[∵ ∠ABC = ∠DBC, ∠ADC = ∠BDC]
Adding ∠BCD on both sides
∠DBC + ∠BDC + ∠BCD = 2∠BCD
180° = 2 ∠BCD[Angle sum property of A]
=> ∠BCD = 90°
Hence, ∠BCD = 90°.

Solution 17.
CBSE Sample Papers for Class 9 Maths Paper 3 17
Given: A ∆ABC in which D and E are the mid points of AB and AC respectively, DE is joined.
To prove: DE || BC and DE = \(\frac { 1 }{ 2 }\)BC
Construction: Draw CF || BA, meeting DE produced in F.
Proof: In ∆AED and ∆CEF
AE = CF (given)
∠AED = ∠CED (V.O.A.)
∠DAE = ∠FCE (alternate interior angles) BD || CF
∴ ∆AED ≅ ∆CEF (By ASA congruency)
=> AD = CF (CPCT)
But AD = BD
=> BD = CF and BD || CF (by construction)
∴ BCFD is a parallelogram.∴DF || BC and DF = BC
=> DE || BC [∵ DF || BC]
DE = \(\frac { 1 }{ 2 }\) DF = \(\frac { 1 }{ 2 }\) BC [∵ DF = BC]
DE || BC and DE = \(\frac { 1 }{ 2 }\) BC
OR
Given: Two parallelograms ABCD and ABEF on the same base AB and between the same parallel lines AB and FC.
CBSE Sample Papers for Class 9 Maths Paper 3 17.1

Solution 18.
In ∆ACF, side CF is produced to B
∴ ∠y = ∠1 + ∠3 …(i)
[exterior angle = sum of interior opposite angles]
In ∆AED, side ED is produced to B
∠1 + ∠x = ∠4 …(ii)
Adding eq. (i) and (ii)
∠1 + ∠x + ∠y = ∠1 + ∠3 + ∠4
⇒∠x + ∠y = ∠3 + ∠4 [∵∠4 = ∠3 angles in the same segment ]
⇒∠x + ∠y = 2∠3 [∵∠AOB = 2∠ACB]
∠x + ∠y = ∠z
Hence ∠x + ∠y = ∠z

Solution 19.
Steps of Construction:
(i) Draw BC = 6 cm
(ii) Construct ∠CBX = 60°
(iii) Along BX, set off BP = 9 cm
(iv) Join CP
(v) Draw the perpendicular bisector of CP to intersect BP at A.
(vi) Join AC, then ∆ABC is the required triangle.
CBSE Sample Papers for Class 9 Maths Paper 3 19

Solution 20.
(i) (3, -3) is the mirror image of (3, 3) in x-axis.
(ii) No mirror image in y-axis.
CBSE Sample Papers for Class 9 Maths Paper 3 20

Solution 21.
Let the outer and inner radii be R cm and r cm respectively.
h = 14 cm, outer surface area = 2πRh = 2 x \(\frac { 22 }{ 7 }\) x R x 14 = (88R) cm²
CBSE Sample Papers for Class 9 Maths Paper 3 21

Solution 22.
TSA of cylinder = 2πrh + 2πr² = 231 …(1)
CSA of cylinder = 2πrh = \(\frac { 2 }{ 3 }\) of (TSA of cylinder)
CBSE Sample Papers for Class 9 Maths Paper 3 22
CBSE Sample Papers for Class 9 Maths Paper 3 22.1

Solution 23.
CBSE Sample Papers for Class 9 Maths Paper 3 23

Solution 24.
Let f(x) = Px² + 5x + r
If (x – 2) is a factor of P(x), then remainder = 0
x – 2 = 0 => x = 2
Remainder = f(2) = P(2)² + 5x² + r = 0
4P + 10 + r = 0
4P + r = -10 ..(i)
CBSE Sample Papers for Class 9 Maths Paper 3 24
CBSE Sample Papers for Class 9 Maths Paper 3 24.1

Solution 25.
Let x ml of the pure alcohol be added to be 15% solution to get 32% alcoholic solution. New volume of alcoholic solution = (800 + x) ml
Quantity of pure alcohol in (800 + x) ml of 32% solution = Quantity of pure alcohol in 800 ml of 15% solution + x ml of pure alcohol
CBSE Sample Papers for Class 9 Maths Paper 3 25

Solution 26.
∠QOS = ∠ROQ + ∠ROS …(i)
∠POS = ∠POR – ∠ROS …(ii)
Subtracting eqn. (i) by (ii)
∠QOS – ∠POS = ∠ROQ – ∠POR + 2∠ROS
∠QOS – ∠POS = (∠ROQ – ∠ROQ) + 2∠ROS (∠ROQ = ∠POR = 90°)
=> 2∠ROS = ∠QOS – ∠POS
=> ∠ROS = \(\frac { 1 }{ 2 }\) [∠QOS – ∠POS]
CBSE Sample Papers for Class 9 Maths Paper 3 26

Solution 27.
CBSE Sample Papers for Class 9 Maths Paper 3 27
(i) ∠DCA = ∠ECB
=> ∠DCA + ∠DCE = ∠ECB + ∠DCE
=> ∠ACE = ∠BCD
Now in AAEC and ABCD
∠DBC = ∠EAC (given)
AC = BC (C is the mid point)
∠ACE = ∠BCD (Proved)
∴ ADBC ≅ AEAC (ASA congruency)
(ii) ADBC ≅ AEAC
DC = EC (CPCT)

Solution 28.
CBSE Sample Papers for Class 9 Maths Paper 3 28
In ∆ABC, F and E are the mid-points of AB and AC respectively.
∴FE || BC and FE = \(\frac { 1 }{ 2 }\) BC = BD
∴FE || BD and FE = BD [∵FE||BC => FE||BD]
=> BDEF is a parallelogram whose diagonals BE and DF intersect each other at X.
∴X is the midpoint of DF.
Similarly, Y is the mid point of DE.
Thus, in ∆DEF, X and Y are the midpoints of DF and DE respectively.
So, XY || FE
CBSE Sample Papers for Class 9 Maths Paper 3 28.1

Solution 29.
In the given frequency distribution, class sizes are different. So, to calculate the adjusted frequency for each class, Minimum class size = 5
CBSE Sample Papers for Class 9 Maths Paper 3 29
CBSE Sample Papers for Class 9 Maths Paper 3 29.1

Solution 30.
Required tarpaulin = Area of shelter = Curved surface area of cuboid + Top area
= 2 (l + b) x h + lb
= 2(4 + 3) x 2.5 + 4 x 3
= 35 + 12
= 47 m²
Values: (i) Care for animal, (ii) Kindness.

We hope the CBSE Sample Papers for Class 9 Maths Paper 3 help you. If you have any query regarding CBSE Sample Papers for Class 9 Maths Paper 3, drop a comment below and we will get back to you at the earliest.

CBSE Sample Papers for Class 9 Maths Paper 2

CBSE Sample Papers for Class 9 Maths Paper 2 is part of CBSE Sample Papers for Class 9 Maths . Here we have given CBSE Sample Papers for Class 9 Maths Paper 2

CBSE Sample Papers for Class 9 Maths Paper 1

Board CBSE
Class IX
Subject Maths
Sample Paper Set Paper 2
Category CBSE Sample Papers

Students who are going to appear for CBSE Class 9 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 2 of Solved CBSE Sample Papers for Class 9 Maths is given below with free PDF download solutions.

Time: 3 Hours
Maximum Marks: 80

General Instructions:

  • All questions are compulsory.
  • Questions 1-6 in Section-A are Very Short Answer Type Questions carrying 1 mark each.
  • Questions 7-12 in Section-B are Short Answer (SA-I) Type Questions carrying 2 marks each.
  • Questions 13-22 in Section-C are Short Answer (SA-II) Type Questions carrying 3 marks each.
  • Questions 23 -30 in Section-D are Long Answer Type Questions carrying 4 marks each.

SECTION-A

Question 1.
If √2 = 1.414 , then \(\sqrt { \frac { (\sqrt { 2 } -1) }{ (\sqrt { 2 } +1) } } =\) ?

Question 2.
If \(\frac { x }{ y } +\frac { y }{ x } =-1\), where x ≠ 0,y ≠ 0, then find the value of x3 – y3.

Question 3.
Who is known as the “Father of Geometry”?

Question 4.
Find the area of the ∆OAB with 0(0, 0). A(4, 0) and B(0, 6).

Question 5.
Two cubes have their volumes in the ratio 1 : 27. Find the ratio of their surface area.

Question 6.
In 50 tosses of a coin, tail appears 32 times. If a coin is tossed at random, what is the probability of getting a head?

SECTION-B

Question 7.
If a + b + c = 0, then \(\left( \frac { { a }^{ 2 } }{ bc } +\frac { { b }^{ 2 } }{ ca } +\frac { c^{ 2 } }{ ab } \right) =?\)

Question 8.
Find the measure of an angle, if six times its complement is 12° less than twice its supplement.

Question 9.
If an angle of a parallelogram is two third of its adjacent angle, find the smallest angle of the parallelogram.

Question 10.
In the adjoining figure, the point D divides the side BC of ∆ABC in the ratio m : n. Prove that \(\frac { ar(\Delta ABD) }{ ar(\Delta ADC) } =\frac { m }{ n } \)
CBSE Sample Papers for Class 9 Maths Paper 2 10

Question 11.
The sides of a triangle are in the ratio 5:12:13 and its perimeter is 150 cm. Find the area of triangle.

Question 12.
Find the mean of the first six prime numbers.

SECTION-C

Question 13.
Rationalise the denominator of \(\frac { \left( \sqrt { 3 } +\sqrt { 2 } \right) }{ \left( \sqrt { 3 } -\sqrt { 2 } \right) } \)
OR
If a and b are rational numbers and \(\frac { \left( \sqrt { 11 } -\sqrt { 7 } \right) }{ \left( \sqrt { 11 } +\sqrt { 7 } \right) } =a-b\sqrt { 77 } \)
Find the value of a and b.

Question 14.
Factorize (p – q)3 + (q – r)3 + (r – p)3

Question 15.
Draw the graph of the equation 2x + 3y = 11. From your graph, find the value of y, when x = -2.

Question 16.
In a quadrilateral ABCD the line segment bisecting ∠C and ∠D meet at E.
Prove that ∠A + ∠B = 2∠CED.

Question 17.
In the adjoining figure, BM ⊥ AC and DN ⊥ AC. If BM = DN, then prove that AC bisect BD.
CBSE Sample Papers for Class 9 Maths Paper 2 17

Question 18.
Without plotting the given points on a graph paper, indicate the quadrants in which they lie
(a) ordinate = 6, abscissa = -3
(b) ordinate = -6, abscissa = 4
(c) abscissa = -5, ordinate = -7
(d) ordinate = 3, abscissa = 5
(e) (-6, 5)
(f) (2,-9)

Question 19.
A well of inner diameter 14 m is dug to a depth of 15 m. Earth taken out of it has been evenly spread all around it to a width of 7 m to form an embankment. Find the height of embankment so formed.

Question 20.
Find the number of coins 1.5 cm in diameter and 0.2 cm thick to be melted to form a right circular cylinder of height 5 cm and diameter of 4.5 cm.

Question 21.
The table given below shows the ages of 75 teachers in a school.
CBSE Sample Papers for Class 9 Maths Paper 2 21
Here 18-29 means from 18 to 29 including both. A teacher from the school is chosen at random. What is the probability that the teacher chosen is
(i) 40 years or more than 40 years old?
(ii) 49 years or less than 49 years old?
(iii) 60 years or more than 60 years old?

Question 22.
Construct a ∆ABC in which BC = 5.6 cm, ∠B = 30° and the difference between the other two sides is 3 cm.

SECTION D

Question 23.
If a and b are rational numbers and \(\frac { 4+3\sqrt { 5 } }{ 4-3\sqrt { 5 } } =a+b\sqrt { 5 } \) Find the value of a and b.

Question 24.
If x + y + z = 0, prove that x3 + y3 + z3 = 3xyz. Without actual calculation find the value of (-12)3 + 73 + 53 using above identity.

Question 25.
A taxi charges RS 20 for the first km and @ RS 12 per km for subsequent distance covered. Taking ‘the distance covered as x km and total fare RS y, write a linear equation depicting the relation in ,x and y
(i) Draw the graph between x and y.
(ii) From your graph find the taxi charges for covering 14 km.

Question 26.
In the given figure, AB || CD. Find the value of x.
CBSE Sample Papers for Class 9 Maths Paper 2 26

Question 27.
In a ∆ABC, the bisectors of ∠B and ∠C intersect each other at a point O. Prove that ∠BOC = 90° + \(\frac { 1 }{ 2 }\)∠A

Question 28.
Prove that the angle subtended by an arc of a circle at the centre is double the angle subtended by it at any point on the remaining part of the circle.

Question 29.
The height of a cone is 30 cm. A small cone is cut off at the top by a plane parallel to the base. If its volume be \(\frac { 1 }{ 27 }\) of the volume of the given cone, at what height above the base, the section has been made?

Question 30.
A doctor suggests two ways for treatment of a particular disease one is by taking medicine only and other is by doing meditation and yoga.
CBSE Sample Papers for Class 9 Maths Paper 2 30
(i) Draw frequency polygon for the given data on the same graph.
(ii) What is the importance of yoga and meditation in our life?

Solutions

Solution 1.
CBSE Sample Papers for Class 9 Maths Paper 2 1

Solution 2.
\(\frac { x }{ y } +\frac { y }{ x } =-1\) ⇒ x² + y² = -xy
⇒ x² + y² + xy = 0
⇒ x3 – y3 = (x – y)(x² + y² + xy) = (x – y) x 0 = 0
⇒ x3 – y3 = 0

Solution 3.
Mathematician Euclid is known as “Father of Geometry’”.

Solution 4.
OA = 4 units, OB = 6 units
ar(∆OAB) = \(\frac { 1 }{ 2 }\) x OA x OB = \(\frac { 1 }{ 2 }\) x 4 x 6 = 12 sq. unit
CBSE Sample Papers for Class 9 Maths Paper 2 4

Solution 5.
Volume of cube = (side)3, surface area of cube = 6(side)2
Let the volume of first cube = a3; and second cube = b3
CBSE Sample Papers for Class 9 Maths Paper 2 5
CBSE Sample Papers for Class 9 Maths Paper 2 5.1

Solution 6.
Probability of getting head
CBSE Sample Papers for Class 9 Maths Paper 2 6

Solution 7.
a + b + c = 0 ⇒ a3 + b3 + c3 = 3abc
CBSE Sample Papers for Class 9 Maths Paper 2 7

Solution 8.
Let the measure of the required angle = x°
Measure of its complement = (90° – x).
Measure of its supplement = (180° – x)
6(90° – x) = 2(180° – x) – 12
⇒ 540° – 6x = 360° – 2x – 12 ⇒ 4x = 192°
⇒ x = 48°
Hence the measure of required angle = 48°.

Solution 9.
Let one angle of the parallelogram be x°.
We know that sum of two adjacent angles of a parallelogram is equal to 180°.
CBSE Sample Papers for Class 9 Maths Paper 2 9

Solution 10.
CBSE Sample Papers for Class 9 Maths Paper 2 10

Solution 11.
Let the sides of the triangle be 5x, 12x and 13x as a, b and c. Then
5x + 12x + 13x = 150 => 30x =150 => x = 5
∴ a = 25 cm, b = 60 cm and c = 65 cm
given 2s = 150 cm => s = 75 cm
(s – a) = 50, (s – b)= 15, (s – c) = 10
CBSE Sample Papers for Class 9 Maths Paper 2 11

Solution 12.
The first six prime numbers are 2, 3, 5, 7, 11 and 13.
CBSE Sample Papers for Class 9 Maths Paper 2 12

Solution 13.
CBSE Sample Papers for Class 9 Maths Paper 2 13
CBSE Sample Papers for Class 9 Maths Paper 2 13.1

Solution 14.
Putting p – q = x,q – r = y and r – p = z
x + y + z = p – q + q – r + r – p = O if x + y + z = 0 then x3 + y3 + z3 = 3xyz
∴ (p – q)3 + (q – r)3 + (r – p)3 = 3(p – q)(q – r)(r – p)

Solution 15.
2x + 3y = 11
CBSE Sample Papers for Class 9 Maths Paper 2 15
CBSE Sample Papers for Class 9 Maths Paper 2 15.1
Line AB is the required graph of 2x + 3y= 11.
Reading the Graph: Given x = -2. Take a point M on the x-axis such that OM = -2.
Draw PM, parallel to they-axis, meeting the line AB at P, it is PM = 5 = y.
So, when x = -2 then y = 5.

Solution 16.
Let CE and DE be the bisector of ∠C and ∠D respectively.
CBSE Sample Papers for Class 9 Maths Paper 2 16

Solution 17.
We want to prove that AC bisect BD i.e., OB = OD
Let AC and BD intersect at O and BM = DN
Now ∴ ∆OND ≅ ∆OMB (By ASA)
=> OD = OB (CPCT)
[ ∵ ∠OND = ∠OMB (each 90°), DN = BM (given), ∠DON = ∠BOM (V.O.A.)]
=> AC bisect BD.

Solution 18.
(a) A(-3, 6) lies in quadrant II
(b) B(4, -6) lies in quadrant IV
(c) C(-5, -7) lies in quadrant III
(d) D(5, 3) lies in quadrant I
(e) E(-6, 5) lies in quadrant II
(f) F(2, -9) lies in quadrant IV

Solution 19.
For well: r = 7m, h = 15m = depth
Volume of the earth dug out = Volume of the well
= Volume of cylinder = πr²h
CBSE Sample Papers for Class 9 Maths Paper 2 19
CBSE Sample Papers for Class 9 Maths Paper 2 19.1

Solution 20.
Each coin is cylindrical in shape.
CBSE Sample Papers for Class 9 Maths Paper 2 20
= 45 x 5 = 225
The number of coins required = 225

Solution 21.
Total number of teachers = 75
(i) Number of teachers who are 40 years or more than 40 years old = 35 + 10 = 45
CBSE Sample Papers for Class 9 Maths Paper 2 21
(ii) Number of teachers who are 49 years or less than 49 years old = 5 + 25 + 35 = 65
CBSE Sample Papers for Class 9 Maths Paper 2 21.1
(iii) Number of teachers who are 60 years or more = 0
CBSE Sample Papers for Class 9 Maths Paper 2 21.2

Solution 22.
Steps of Construction:
(i) Draw BC = 5.6 cm
(ii) Construct ∠CBX = 30°
(iii) Set off BP = 3 cm
(iv) Join PC
(v) Draw the right bisector of PC, meeting BP produced at A.
(vi) Join AC. Then ∆ABC is the required triangle.
CBSE Sample Papers for Class 9 Maths Paper 2 22

Solution 23.
CBSE Sample Papers for Class 9 Maths Paper 2 23

Solution 24.
x + y + z = 0 => x + y = – z => (x+y)3 = (-z)3
=> x3 + y3 + 3xy (x + y) = -z3
=> x3 + y3 + 3xy (-z) = -z3
=> x3 + y3 – 3xyz = -z3
=> x3 + y3 + z3 – 3xyz = 0
=> x3 + y3 + z3 = 3xyz
Putting x = -12, y = 7, z = 5
We get x + y + z = -12 + 7 + 5 = -12 + 12 = 0 then x3 + y3 + z3 = 3xyz
=> (-12)3 + (7)3 + (5)3 = 3 x (-12) x 7 x 5
= -3 x 7 x 60
= -21 x 60
= -1260
(-12)3 + 73 + 53 = -1260.

Solution 25.
y = 20 + 12 (x – 1) = 20 + 12x – 12
=> y = 12x + 8
CBSE Sample Papers for Class 9 Maths Paper 2 25
On the graph paper take distance along x-axis and fare (in Rs) along y-axis. We plot the points A(6, 80) and B(11, 140) on the graph paper. Join AB and produce it on both sides to obtain the required graph.
From the graph, when x = 14, we find y = Rs 176.
CBSE Sample Papers for Class 9 Maths Paper 2 25.1

Solution 26.
CBSE Sample Papers for Class 9 Maths Paper 2 26
Through E draw a line GEH || AB || CD
Now GE || AB and EA is transversal
∴ ∠GEA = ∠EAB = 50°
[Alternate Interior Angles]
Again EH || CD and EC is a transversal
∠HEC + ∠ECD = 180°
[Cointerior angles of the same side of transversal]
=> ∠HEC + 100° = 180°
=> ∠HEC = 80°
Now GEH is a straight angle
∠GEA + ∠AEC + ∠HEC = 180°
=> 50° + x° + 80° =180° => x = 50°

Solution 27.
In ∆ABC we have
∠A + ∠B + ∠C = 180°
CBSE Sample Papers for Class 9 Maths Paper 2 27

Solution 28.
Given: A circle C(O, r) in which arc AB subtends ∠AOB at the centre and ∠ACB at any point C on the remaining part of the circle.
To prove: (i) and (ii) ∠AOB = 2 ∠ACB, when AB is a minor arc or a semicircle.
(iii) Reflex ∠AOB = 2∠ACB, when AB is a major arc.
Construction: Join AB and CO. Produce CO to a point D outside the circle.
CBSE Sample Papers for Class 9 Maths Paper 2 28
We know that when one side of a triangle is produced then the exterior angle so formed is equal to the sum of the interior opposite angles.
∴ ∠AOD = ∠OAC + ∠OCA
∠BOD = ∠OBC + ∠OCB
[∵ OC = OA = r ,OC = OB = r]
∠AOD = 2∠OCA and ∠BOD = 2∠OCB
In Figure (i) and Figure (ii) i.e., Case (i) and Case (ii)
∠AOD + ∠BOD = 2∠OCA + 2∠OCB => ∠AOB = 2(∠OCA + ∠OCB)
=> ∠AOB = 2∠ACB
In Figure (iii) i.e., Case (iii)
∠AOD + ∠BOD = 2∠OCA + 2∠OCB
=> Reflex ∠AOB = 2 (∠OCA + ∠OCB) => Reflex ∠AOB = 2∠ACB

Solution 29.
Let the smaller cone have radius r and height h cm and let the radius of the given original cone be R cm.
CBSE Sample Papers for Class 9 Maths Paper 2 29
CBSE Sample Papers for Class 9 Maths Paper 2 29.1

Solution 30.
(i) We take two imagined classes, one at the beginning, namely (10-20) and the other at the end, namely (70-80) each with frequency zero.
With these two classes, we have the following frequency table:
CBSE Sample Papers for Class 9 Maths Paper 2 30
Importance of Yoga and Meditation:
1. Meditation gives you an experience, an inner state, where what is you and what is your is separated.
2. By meditation life seems to be flowing without conflict and just feel more cohesive.
3. Yoga is important for us to achieve:
(i) Good Health
(ii) Success
(iii) Overall well being
(iv) For peace, joy and love
(v) For inner exploration.

We hope the CBSE Sample Papers for Class 9 Maths Paper 2 help you. If you have any query regarding CBSE Sample Papers for Class 9 Maths Paper 2, drop a comment below and we will get back to you at the earliest.

CBSE Sample Papers for Class 9 Maths Paper 5

CBSE Sample Papers for Class 9 Maths Paper 5 is part of CBSE Sample Papers for Class 9 Maths . Here we have given CBSE Sample Papers for Class 9 Maths Paper 5

CBSE Sample Papers for Class 9 Maths Paper 5

Board CBSE
Class IX
Subject Maths
Sample Paper Set Paper 5
Category CBSE Sample Papers

Students who are going to appear for CBSE Class 9 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 5 of Solved CBSE Sample Papers for Class 9 Maths is given below with free PDF download solutions.

Time: 3 Hours
Maximum Marks: 80

General Instructions:

  • All questions are compulsory.
  • Questions 1-6 in Section-A are Very Short Answer Type Questions carrying 1 mark each.
  • Questions 7-12 in Section-B are Short Answer (SA-I) Type Questions carrying 2 marks each.
  • Questions 13-22 in Section-C are Short Answer (SA-II) Type Questions carrying 3 marks each.
  • Questions 23 -30 in Section-D are Long Answer Type Questions carrying 4 marks each.

SECTION-A

Question 1.
Write the value of \(\frac { \sqrt { 32 } +\sqrt { 48 } }{ \sqrt { 8 } +\sqrt { 12 } } \)
OR
Find \(\sqrt [ 4 ]{ \sqrt [ 3 ]{ { 2 }^{ 2 } } } \)

Question 2.
For what value of a, x – 3 is a factor of x3 + x2 – 17x + a?

Question 3.
In figure below, ∆PQR is an isosceles right triangle right angled at Q. Find angle P (∠P).
CBSE Sample Papers for Class 9 Maths Paper 5 3

Question 4.
In a parallelogram ABCD, E and F are any two points on the sides AB and BC respectively. If ar (∆DCE) is 12 cm², then find ar (∆ADF).
CBSE Sample Papers for Class 9 Maths Paper 5 4

Question 5.
What is the volume of the hollow right circular cylinder?

Question 6.
In a class consisting of 18 boys and 22 girls, one student is absent. Find the probability that the absent student is boy.

SECTION-B

Question 7.
If \(\frac { { x }^{ 2 }+1 }{ x } =7\), then find the value of \({ x }^{ 2 }+\frac { 1 }{ { x }^{ 2 } } \)

Question 8.
Find the angle which is two times its supplementary angle.

Question 9.
Which of the following points lie on the x-axis? Show the position of other points also.
A (1, 1), B (1, 0), C (0, 1), D (0, 0), E (-1, 0), F (0, -1) G (4, 0), H (0, 7)

Question 10.
Answer the following:
(i) A point lies on y-axis, then which coordinate is zero?
(ii) If a point is at a distance of 2 units from y-axis and 3 units from x-axis. Write the coordinates.

Question 11.
Into a circular drum of radius 4.2 m and height 3.5 m, how many full bags of wheat can be emptied if the space required for wheat on each bag is 2.1 cubic m? (Take π = 3.14)

Question 12.
Find the median of first 11 multiples of 3.

Question 13.
Simplify
CBSE Sample Papers for Class 9 Maths Paper 5 13
OR
If 52x-1 – (25)x-1 = 2500, then find the value of x.

Question 14.
If 3x + y + z = 0, show that 27x3 + y3 + z3 = 9xyz.
OR
If a + b = c, then show that b² + ac = c² – ab.

Question 15.
In the given figure, ∠ABC = 60°, ∠BCE = 25°, ∠DCE = 35° and ∠CEF = 145°. Prove that AB || EF.
CBSE Sample Papers for Class 9 Maths Paper 5 15

Question 16.
Find the value of x and y, if (x + 4, 3y – 2) = (7, -5).

Question 17.
Show that if the diagonals of a quadrilateral bisect each other at right angles, then it is a rhombus.
OR
Show that the diagonals of a square are equal and bisect each other at right angle.

Question 18.
If the non-parallel sides of a trapezium are equal, prove that it is cyclic.
CBSE Sample Papers for Class 9 Maths Paper 5 18
OR
In the following figure, AB is equal to the radius of the circle. Find the value of ∠AMB, if ‘O’ is the centre of the circle.

Question 19.
Construct a triangle XYZ in which ∠Y = 30°, ∠Z = 90° and XY + YZ + ZX = 11 cm.

Question 20.
An isosceles triangle with base 48 cm has area 240 sq cm. Find the remaining two sides of the triangle.

Question 21.
A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of Rs 498.96. If the cost of white-washing is Rs 2.00 per square meter, find the
(i) Inside surface area of the dome
(ii) Volume of the air inside the dome.

Question 22.
A jar contains 3000 white, black and red beads. The beads are thoroughly mixed and a sample of 60 is taken. The sample is found to contain 17 white beads, 32 black beads and 11 red beads. Estimate the number of beads of each colour in the jar.

SECTION-D

Question 23.
If 2a = 3b = 6c, then show that \(c=\frac { ab }{ a+b }\)

Question 24.
If both (x – 2) and \(x-\frac { 1 }{ 2 }\) are factors px² + 5x + 8, show that \(\frac { p }{ r }=1\)

Question 25.
In figure below, AC = AE, AB = AD and ∠BAD = ∠EAC. Show that BC = DE.
CBSE Sample Papers for Class 9 Maths Paper 5 25

Question 26.
Bisectors of angle A, B and C of a triangle ABC intersect its circumcircle at D, E and F respectively.Prove that the angles of a triangle DEF are 90° – \(\frac { 1 }{ 2 }\)A, 90° – \(\frac { 1 }{ 2 }\)B, and 90° – \(\frac { 1 }{ 2 }\)C

Question 27.
A cylinder is within the cube touching all the vertical faces. A cone is inside the cylinder. If their heights are same with the same base. Find the ratio of their volumes.

Question 28.
Construct a combined histogram and frequency polygon for the following frequency distribution.
CBSE Sample Papers for Class 9 Maths Paper 5 28

Question 29.
ABC is a triangle right angled at C. A line through the mid¬point M of hypotenuse AB and parallel to BC intersect AC at D, show that:
(i) D is the mid-point of AC.
(ii) MD ⊥ AC
(iii) CM = MA = \(\frac { 1 }{ 2 }\)AB
CBSE Sample Papers for Class 9 Maths Paper 5 29

Question 30.
Kartikeya and Pallavi of class IX decided to collect Rs 25 for class cleanliness. Write it in linear equations in two variables. Also draw the graph. What values of both the students are depicted here?

Solutions

Solution 1.
CBSE Sample Papers for Class 9 Maths Paper 5 1

Solution 2.
x – 3 = 0 => x = 3, p(x) = x3 + x2 – 17x + a
For factor x – 3, remainder p(3) = 0
P(3) = (3)3 + (3)2 – 17 x 3 + a = 0 => 27 + 9 – 51 + a = 0
a = 51 – 36 = 15 => a = 15

Solution 3.
∠P = ∠R (Isosceles A), ∠Q = 90°
∠P + ∠Q + ∠R = 180° => ∠P + ∠P + 90° = 180°
2 ∠P = 90° =>∠P = 45°

Solution 4.
ar (∆ADF) = \(\frac { 1 }{ 2 }\) ar (||gm ABCD) = ar (∆DCE)
ar (∆ADF) = ar (∆DCE)
ar (∆ADF) = 12 cm²
[In same base and between same parallels area of triangle is half the area of parallelogram.

Solution 5.
Volume = πh (R² – r²) cubic unit.

Solution 6.
Total students = 18 + 22 = 40, Boys = 18, girls = 22
P (Absent boys) = p (E) = \(\frac { 18 }{ 40 }\) = \(\frac { 9 }{ 20 }\)

Solution 7.
CBSE Sample Papers for Class 9 Maths Paper 5 7

Solution 8.
Let angle be x. It supplementary angle = (180 – x)°
=> x = 2(180 – x)
=> x = 360 – 2x =>3x = 360° => x = 120°

Solution 9.
(i) Points lie on x-axis may be (a, 0) => B (1, 0), E (-1, 0), G (4, 0).
(ii) Points lie on y-axis may be (0, b) => C (0, 1), F (0, -1), H (0, 7)
(in) Point lies on origin => D(0, 0)
(iv) Point lies of I quadrant may be (x, y) = (1, 1).

Solution 10.
(i) If a point lies on y-axis, then its x-coordinate will be zero, i.e., it is represented by (0, b).
(ii) Coordinates of points be (2, 3).

Solution 11.
r = 4.2m
h = 3.5m
CBSE Sample Papers for Class 9 Maths Paper 5 11
Complete or full bags of wheat = 92 bags.

Solution 12.
First 11 multiples of 3 = 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33
Median = Middle term of the observations
Total terms = n = 11
CBSE Sample Papers for Class 9 Maths Paper 5 12
Median = 18 (6th term)

Solution 13.
CBSE Sample Papers for Class 9 Maths Paper 5 13
CBSE Sample Papers for Class 9 Maths Paper 5 13.1

Solution 14.
If a + b + c = 0 then a3 + b3 + c3 = 3abc
If a = 3x, b = y, c = z
then a + b + c = 3x + y + z = 0
and, a3 + b3 + c3 = 3 abc
(3x)3 + (y3) + (z)3 = 3 x (3x) x y x z
27 x3 + y3 + z3 = 9 xyz
OR
Since a + b = c
On squaring both sides (a + b)² = c²
a² + b² + 2 ab = c²
a² + b² + ab + ab = c²
(a² + ab) + b² = c² – ab
a (a + b) + b² = c² – ab
ac + b² = c² – ab [since a + b = c]
b² + ac = c² – ab

Solution 15.
∠BCD = ∠BCE + ∠DCE
= 25° + 35° = 60°
CBSE Sample Papers for Class 9 Maths Paper 5 15

Solution 16.
[(x + 4), (3y – 2)] = (7, -5)
On comparing
x + 4 = 7 ⇒ x = 7 – 4 = 3 ⇒ x = 3
3y – 2 = -5 ⇒ 3y = -5 + 2 = -3
⇒ y = \(\frac { -3 }{ 3 }\) = -1
x = 3,y = -1

Solution 17.
CBSE Sample Papers for Class 9 Maths Paper 5 17
Given: In quadrilateral ABCD
OA= OC and ∠AOB = ∠BOC = ∠COD
OB = OD = ∠DOA = 90°
To prove: ABCD is a rhombus
i.e. ABCD is a parallelogram having all sides equal.
Proof: In ∆AOD and ∆COD
OA = OC(Diagonals bisect each other)
∠AOD = ∠COD (Each 90°)
OD = OD (Common)
∴ ∆AOD ≅ ∆COD (By S.A.S)
=> AD = CD (By CPCT)
Similarly, AD = AB, and CD = BC
So, AB = BC = CD = DA
Since opposite sides of a quadrilateral ABCD are equal, so it is a parallelogram.
Here, all sides of the parallelogram are equal. So it is rhombus.
OR
CBSE Sample Papers for Class 9 Maths Paper 5 17.1
Given: ABCD is a square and diagonals AC and BD intersect each other at O.
To Prove: AC = BD, OA = OC, OB = OD and ∠AOB = 90°
Proof: In ∆ABC and ∆DCB
AB = DC
∠ABC = ∠DCB
BC = BC
∴ ∆ABC ≅ ∆DCB
AC = DB
Hence the diagonals of a square are equal in length.
In ∆AOB and ∆COD ,
∠AOB = ∠COD
∠ABO = ∠CDO
AB = CD
∴ ∆AOB ≅ ∆COD
=> AO = CO and OB = OD
Hence diagonals of a square bisect each other.
Now in ∆AOB and ∆COB
OA = OC; AB = BC and BO = BO => ∴ ∆AOB ≅ ∆COB(SSS Congruence)
∠AOB = ∠COB (CPCT)
∠AOB = ∠COB
But ∠AOB + ∠COB = 180° (Linear pair)
2 ∠AOB = 180°
∠AOB = \(\frac { 180 }{ 2 }\) = 90°
∠AOB = 90°
Hence, the diagonals of a square bisect each other at right angle.

Solution 18.
CBSE Sample Papers for Class 9 Maths Paper 5 18
Given: In trapezium ABCD, AB || DC and BC = AD
To Prove: ABCD is a cyclic quadrilateral.
Construction: Draw A ⊥ DC and BN ⊥ DC
Proof: In ∆AMD and ∆BNC
AD = BC (Given)
∠AMD = ∠BNC (Each 90°)
AM = BM
(Perpendicular distance between two parallel lines are equal)
∴ ∆AMD ≅ ∆BNC (By RHS congruency)
∴∠ADC = ∠BCD …(1) (CPCT)
∵ ∠BAD and ∠ADC are on the same side of transversal AD.
∠BAD + ∠ADC = 180° …(2)
=> ∠BAD + ∠BCD = 180° (∵ ∠ADC = ∠BCD)
=> This shows that opposite angles are supplementary.
=> ABCD is a cyclic quadrilateral.
OR
CBSE Sample Papers for Class 9 Maths Paper 5 18.1
Given: O is the centre of circle and AB is equal to the radius.
Construction: Join OA, OB and OC.
To Find: ∠AMB
In ∆OAB, OA = OB = OC (Each equal to radius)
=> ∆OAB is an equilateral triangle.
=> ∠AOB = 60°
=> ∠AOB = \(\frac { 180 }{ 2 }\)= 90°
∠ACB = 30°
(Angle subtended by an arc at the centre is double that subtended at any part of the circle)
But ∠DAC = 90° (Angle in the semi-circle is 90°)
Now ∠CAM = 180°- 90° = 90° (Linear pair)
Now in ∆ (CAM)
∠A + ∠C + ∠M= 180°
90° + 30° + ∠M = 180°
∠M = 180° – 90° – 30° = 60°
∠AMB = 60°

Solution 19.
Steps of Construction:
1. Draw a line segment AB of 11 cm (XY + YZ + ZX =11 cm).
2. Construct an angle ∠PAB = 30° at point A and an angle ∠OBA of 90° at point B.
3. Bisect ∠PAB and ∠QBA. Let these bisectors intersect each other at point X.
4. Draw perpendicular bisector ST of AX and UV of BX.
5. Let ST intersects AB at Y and UV intersects AB at Z. Join XY, XZ.
Thus, ∆XYZ is the required triangle.
CBSE Sample Papers for Class 9 Maths Paper 5 19

Solution 20.
Let two sides of Isosceles triangle = x cm
Area = 240 cm², Here, a = x, b = x, c = 48 cm
CBSE Sample Papers for Class 9 Maths Paper 5 20
Hence two sides of Isosceles triangle = 26 cm.

Solution 21.
(i) Cost occured in white-washing the dome from inside = Rs 498.96
Cost of white-washing 1 m² = Rs 2
CBSE Sample Papers for Class 9 Maths Paper 5 21
V = 523.908 m³ = 523.9 m³ approximately.
Hence, volume of air inside the dome is 523.9 m³.

Solution 22.
Sample sum = 17 + 32 + 11 = 60
CBSE Sample Papers for Class 9 Maths Paper 5 22
Hence number of beads
(i) White = 850
(ii) Black = 1600
(iii) Red = 550

Solution 23.
2a = 3b ⇒ 2 = 3b/a ….(1)
6c = 3b ⇒ 6 = 3b/c …..(2)
CBSE Sample Papers for Class 9 Maths Paper 5 23
CBSE Sample Papers for Class 9 Maths Paper 5 23.1

Solution 24.
Let f(x) = px² + 5x + r. If (x – 2) and \(x-\frac { 1 }{ 2 }\) are factors of polynomial f(x), then remainder must be zero.
If x – 2 = 0, => x = 2
Remainder = f(2) = p(2)² + 5(2) + r = 0
4p + 10 + r = 0
4p + r = – 10 …(1)
CBSE Sample Papers for Class 9 Maths Paper 5 24

Solution 25.
∠BAD = ∠EAC (Given)
Adding ∠DAC on both sides
∠BAD + ∠DAC = ∠EAC + ∠DAC
∠BAC = ∠DAE …(1)
In ∆BAC and ∆ADE
AC = AE (Given)
∠BAC = ∠DAE (Proved in Eqn. (1)]
=> AB = AD (Given)
∴ ∆ABC ≅ ∆DAE (By SAS congruency)
BC = DE (CPCT)
Hence, BC = DE .

Solution 26.
It is given that BF is the bisector of ∠B
CBSE Sample Papers for Class 9 Maths Paper 5 26
CBSE Sample Papers for Class 9 Maths Paper 5 26.1

Solution 27.
Let the length of each edge of the cube be ‘a’ units.
V1 = Volume of cube = a3 cubic units …(1)
Since a cylinder is within the cube and touches all the faces of the cube.
r = Radius of the base of the cylinder = \(\frac { a }{ 2 }\)
H = Height of the cylinder = a
CBSE Sample Papers for Class 9 Maths Paper 5 27
CBSE Sample Papers for Class 9 Maths Paper 5 27.1

Solution 28.
For frequency polygon 2 more class intervals (-10 – 0) and (50 – 60) are taken and classmarks of all class intervals are taken.
The class marks are -5, 5, 15, 25, 35,45, 55.
The graph is plotted on graph paper. Coordinates on both axes are given here in the graph paper.
CBSE Sample Papers for Class 9 Maths Paper 5 28

Solution 29.
(i) In ∆ABC, M is the mid-point of AB and MD || BC so, D is the mid-point of AC.
(Converse .of mid-point theorem)
(ii) As DM || CB and AC is a transversal line for them
∠MDC + ∠DCB = 180° (Co-interior angles)
∠MDC + 90° = 180°
∠MDC = 90°
MD⊥AC
(iii) Join MC
In ∆AMD and ∆CMD AD = CD (D is mid-point of side AC)
∠ADM = ∠CDM (Each 90°)
DM = DM (Common)
CBSE Sample Papers for Class 9 Maths Paper 5 29
CBSE Sample Papers for Class 9 Maths Paper 5 29.1

Solution 30.
Let Kartikaya collected = Rs x
Pallavi collected = Rs y
ATQ, Linear Equation in two variables
x + y = 25
(i) If x = 10,y = 25 – x = 25 – 10 = 15
(ii) If x = 15, y = 25 – 15 = 10
CBSE Sample Papers for Class 9 Maths Paper 5 30
CBSE Sample Papers for Class 9 Maths Paper 5 30.1
The graph is plotted.
Values: (i) Co-operation
(ii) Awareness about cleanliness,
(iii) Responsibility.

We hope the CBSE Sample Papers for Class 9 Maths Paper 5 help you. If you have any query regarding CBSE Sample Papers for Class 9 Maths Paper 5, drop a comment below and we will get back to you at the earliest.

CBSE Sample Papers for Class 9 Maths Paper 1

CBSE Sample Papers for Class 9 Maths Paper 1 is part of CBSE Sample Papers for Class 9 Maths . Here we have given CBSE Sample Papers for Class 9 Maths Paper 1

CBSE Sample Papers for Class 9 Maths Paper 1

Board CBSE
Class IX
Subject Maths
Sample Paper Set Paper 1
Category CBSE Sample Papers

Students who are going to appear for CBSE Class 9 Examinations are advised to practice the CBSE sample papers given here which is designed as per the latest Syllabus and marking scheme as prescribed by the CBSE is given here. Paper 1 of Solved CBSE Sample Papers for Class 9 Maths is given below with free PDF download solutions.

Time: 3 Hours
Maximum Marks: 80

General Instructions:

  • All questions are compulsory.
  • Questions 1-6 in Section-A are Very Short Answer Type Questions carrying 1 mark each.
  • Questions 7-12 in Section-B are Short Answer (SA-I) Type Questions carrying 2 marks each.
  • Questions 13-22 in Section-C are Short Answer (SA-II) Type Questions carrying 3 marks each.
  • Questions 23 -30 in Section-D are Long Answer Type Questions carrying 4 marks each.

SECTION-A

Question 1.
CBSE Sample Papers for Class 9 Maths Paper 1 1

Question 2.
What is the degree of zero polynomial?

Question 3.
In ∆ABC, BC is produced to D. If ∠ABC = 40° and ∠ACD = 120°, then ∠A = ?

Question 4.
Write the signs of abscissa and ordinate of a point in quadrant (II).

Question 5.
The total surface area of a cube is 216 cm². Find its volume.

Question 6.
Find the slope of the line 2x + 3y – 4 = 0.

SECTION-B

Question 7.
If a + b + c = 0, then a³ + b³ + c³ = ?

Question 8.
Find four different solutions of 2x + y = 6

Question 9.
The base of an isosceles triangle is 16 cm and its area is 48 cm². Find the perimeter of a triangle.

Question 10.
If the mean of five observations x, x + 2, x + 4, x + 6 and x + 8 is 13. Find the value of x.

Question 11.
1500 families with 2 children each were selected randomly and the following data were recorded.
CBSE Sample Papers for Class 9 Maths Paper 1 11
Out of these families, one family is selected at random. What is the probability that the selected family has
(i) 2 girls
(ii) no girl.

Question 12.
Two coins are tossed 1000 times and the outcomes are recorded as under.
CBSE Sample Papers for Class 9 Maths Paper 1 12
A coin is thrown at random. What is the probability of getting
(i) at most one head ?
(ii) atleast one head ?

SECTION-C

Question 13.
If x = 3 + √8 , find the value of \(\left( { x }^{ 2 }+\frac { 1 }{ { x }^{ 2 } } \right) \)

Question 14.
If p = 2 – a, prove that a³ + 6ap + p³ – 8 = 0.

Question 15.
In the given figure, prove that x = α + β + γ.

Question 16.
If the bisector of the vertical angle of a triangle bisect the base, prove that the triangle is Isosceles.

Question 17.
The sides BA and DC of quad. ABCD are produced as shown in the given figure. Prove that x° + y° = a° + b°.

Question 18.
In an equilateral triangle, prove that the centroid and the circumcentre coincide.

Question 19.
Construct a Δ ABC whose perimeter is 14 cm and sides are in the ratio 2:3:4.

Question 20.
Plot the points A(-5, 2), B(-4, -3), C(3, -2) and D(6, 0) on a graph paper. Write the name of figure formed by joining them.

Question 21.
The diameter of a roller, 120 cm long is 84 cm. If it takes 500 complete revolutions to level a playground. Find the cost of levelling it at 75 paise per square metre.

Question 22.
The internal and external diameters of a hollow hemispherical vessel are 20 cm and 28 cm respectively. Find the cost of painting the vessel all over at 14 paise per cm².

SECTION-D

Question 23.
Show that
CBSE Sample Papers for Class 9 Maths Paper 1 23

Question 24.
Prove that x3 + y3 + z3 – 3xyz =(x + y + z) (x2 + y2 + z2 – xy – yz – zx). Hence find the value of x3 + y3 + z3 if x + y + z = 0.

Question 25.
In a ∆ABC, the side AB and AC are produced to P and Q respectively. The bisector of ∠PBC and ∠QCB intersect at a point O. Prove that ∠BOC = 90° – \(\frac { 1 }{ 2 }\) ∠A.

Question 26.
In each of the following figures, AB || CD. Find the value of x in each case.
CBSE Sample Papers for Class 9 Maths Paper 1 26

Question 27.
Draw the graph of the equation 3x + 2y = 12. At what points does the graph cut the x-axis and the y-axis.

Question 28.
A river 2m deep and 45 m wide is flowing at the rate of 3 km per hour. Find the volume of water that runs into the sea per minute.
Now answer these questions.
1. Why we should preserve and not waste the water and other natural resources? Write one method to restore the water at your home.
2. Why it is necessary to clean all rivers in the country?

Question 29.
The mean of 25 observations is 36. If the mean of first 13 observations is 32 and that of last 13 observations is 39, find the 13th observation.

Question 30.
Plot the points A(2, 5), B(-2, 2) and C(4, 2) on a graph paper. Join AB, BC and AC. Calculate the area of ∆ABC.

Solutions

Solution 1.
CBSE Sample Papers for Class 9 Maths Paper 1 1

Solution 2.
Degree of zero polynomial is not defined.

Solution 3.
CBSE Sample Papers for Class 9 Maths Paper 1 3
∠A + ∠B = ∠ACD
⇒ ∠A + 40° = 120°
⇒ ∠ A = 80°

Solution 4.
The points in quadrant II are in the form (-, +).

Solution 5.
The Total Surface Area of cube (T.S.A.) = 6a² = 216
=> a² = 36 => a = √36 = 6 cm
Volume of cube = (a)3 = (6)3 = 216 cm3
Volume of cube = 216 cm3

Solution 6.
2x + 3y – 4 = 0 ⇒ 3y = – 2x + 4
CBSE Sample Papers for Class 9 Maths Paper 1 6

Solution 7.
a + b + c = 0 ⇒ a + b = – c
⇒ (a + b)3 = (- c)3 ⇒ a3 + b3 + 3ab (a + b) = -c3
⇒ a3 + b3 + 3ab (- c) = -c3 ⇒ a3 + b3 + c3 = 3abc

Solution 8.
y = 6 – 2x
(i) If x = 1,y = 6 – 2 = 4
(ii) If x = 2,y = 6 – 4 = 2
(iii) If x = 3,y = 6 – 6 = 0
(iv) If x = 4,y = 6 – 8 = -2
CBSE Sample Papers for Class 9 Maths Paper 1 8

Solution 9.
b =16 cm, area = 48 cm²
CBSE Sample Papers for Class 9 Maths Paper 1 9
Perimeter of Isosceles triangle = 2a + b = 20 + 16 = 36 cm.

Solution 10.
Mean of the given observations
CBSE Sample Papers for Class 9 Maths Paper 1 10

Solution 11.
Total number of families = 1500
CBSE Sample Papers for Class 9 Maths Paper 1 11
CBSE Sample Papers for Class 9 Maths Paper 1 11.1

Solution 12.
Total number of tosses = 266 + 540 + 194 = 1000
(i) At most one head = Number of times one head or no head appears
= 540+ 194 = 734
P(E1) = P(at most one head) = \(\frac { 734 }{ 1000 }\) =0.734
(ii) Atleast one head = Number of times one head or two head appears
= 540 + 266 = 806
P(E2) = P(atleast one head) = \(\frac { 806 }{ 1000 }\) = 0.806

Solution 13.
x + 3√8
CBSE Sample Papers for Class 9 Maths Paper 1 13

Solution 14.
We have p = 2 – a => a + p + (-2) = 0
=> Putting a = x,p = y and (-2) = z.
we get a + p + (-2) = 0 =>x + y + z = 0
⇒a3 + p3 + (-2)3 = 3 × a × p × (-2) [If x + y + z = 0 then x3 + y3 + z3 = 3xyz]
⇒a3 + p3 + (-2)3 = -6ap
⇒a3 + 6ap + p3 – 8 = 0

Solution 15.
CBSE Sample Papers for Class 9 Maths Paper 1 15
Join B and D and produce BD to E.
p + q = β and s + t = x
Side BD of A ABD is produced to E
∴ p + α = s ..(1)
Side BD of A CBD is produced to E.
∴ q + γ = t ..(2)
Adding (1) and (2)
(p + α) + (q + γ) = s + 1
(p + q) + (α) + (γ) = x
β + α + γ = x
⇒ x = α + β + γ

Solution 16.
CBSE Sample Papers for Class 9 Maths Paper 1 16
Given: ∆ AABC in which AD is the bisector of ∠ A, which meets BC in D such that BD = DC.
To prove: AB = AC
Construction: Produce AD to E such that AD = DE and join EC.
Proof: In ∆ABD and ∆ECD
BD = DC (given)
AD = DE (by construction)
∠ADB = ∠EDC (V.O.A)
=> ∴ ∆ABD ≅ ∆ECD
∴ ∆ABC ≅ ∆ECD
=> AB = EC and ∠1 = ∠3 …(2) (CPCT)
Also ∠1 = ∠2 …(3) [∵AD bisects ∠A]
∴ ∠2 = ∠3 [using (2)and(3)]
=> EC = AC …(4) [side opposite to equal angles]
=> AB = AC [using (1)and(4)]
=> ∆ABC is Isosceles.

Solution 17.
We have ∠ A + b° = 180° (Linear pair)
=> ∠A = 180° – b° …(1)
Also ∠C + a° = 180° (Linear pair)
∠C = 180° – a° …(2)
CBSE Sample Papers for Class 9 Maths Paper 1 17

Solution 18.
CBSE Sample Papers for Class 9 Maths Paper 1 18
Let ∆ ABC be the given equilateral triangle and let its median AD,
BE and CF intersect at G.
Then G is the centroid of ∆ ABC
In ∆ BCE and ∆ CBF
BC = CB (common)
∠B = ∠C [each 60°]
CBSE Sample Papers for Class 9 Maths Paper 1 18.1
This shows that G is the circumcentre of ∆ ABC
=> G is the centroid as well as circumcentre of ∆ ABC
Note: Centroid: The point of intersection of the medians of a triangle is called centroid.
The centroid of the triangle is the point located at \(\frac { 2 }{ 3 }\) of the distance from a vertex along the median.
Circumcentre: The centre of the circumcircle of the triangle is called the circumcentre.

Solution 19.
Steps of construction:
(i) Draw a line segment PQ =14 cm. Draw a ray PX making an acute angle with PQ and draw in the downward direction.
(ii) From P, mark set of (2 + 3 + 4) = 9 equal distance along PX.
(iii) Mark points L, M, N on PX such that PL = 2 cm, LM = 3 cm and MN = 4 cm.
(iv) Join NQ. Through L and M draw LB || NQ and MC || NQ. Cutting PQ at B and C respectively.
(v) With B as centre and radius BP draw an arc. With C as centre and radius CQ draw another arc, cutting the previous arc at A.
(vi) Join AB and AC. ∆ ABC is the required triangle.
CBSE Sample Papers for Class 9 Maths Paper 1 19

Solution 20.
Points A(-5, 2), B(-4, -3), C (3, -2) and D(6, 0) are shown on graph paper.
CBSE Sample Papers for Class 9 Maths Paper 1 20
The figure formed by joining them is called quadrilateral.

Solution 21.
Radius of roller = r = 42 cm, Length = h = 120 cm
Area covered by the roller in 1 revolution = C.S.A. of the roller = 2πrh sq. unit.
CBSE Sample Papers for Class 9 Maths Paper 1 21

Solution 22.
Outer radius of the vessel R = 14 cm
Inner radius of the vessel = r = 10 cm
Area of the outer surface = 2πR² cm²
= (2π x 14 x 14) cm² = 392 π cm²
Area of the inner surface = 2πt² cm²
= (2π x 10 x 10) cm² = 200 π cm²
Area of the ring (shaded) at the top = π(R² – r²)
= π[( 14)² – (10)²] = π(14 + 10) (14 – 10)
= 96 π cm²
Total area to be painted = 392 π + 200 π + 96 π
= 688 π cm²
CBSE Sample Papers for Class 9 Maths Paper 1 22

Solution 23.
CBSE Sample Papers for Class 9 Maths Paper 1 23
CBSE Sample Papers for Class 9 Maths Paper 1 23.1

Solution 24.
x3 + y3 + z3 – 3xyz = (x3 + y3) + z3 – 3xyz
x3 + y3 + z3 – 3xyz = [(x + y)3 – 3xy(x + y)] + z3 – 3xyz [let x + y = u]
= u3 – 3xyu + z3 – 3xyz
= u3 + z3 – 3xy (u + z) = (u3 + z3) – 3xy (u + z)
= (u + z) (u2 – uz + z2) – 3xy (u + z) = (u + z) [u2 + z2 – uz – 3xy]
= (x + y + z) [(x + y)2 + z2 – (x + y)z – 3xy] [u = x + y]
= (x + y + z) [x2 + y2 + z2 + 2xy – xz -yz – 3xy]
x3 + y3 + z3 – 3xyz = (x + y + z) (x2 + y2 + z2 – xy – yz – zx)
if x + y + z = 0
x3 + y3 + z3 – 3xyz = 0 × (x2 + y2 + z2 – xy – yz – zx)
x3 + y3 + z3 – 3xyz = 0
x3 + y3 + z3 = 3xyz

Solution 25.
We have ∠B + ∠CBP = 180° (Linear pair)
CBSE Sample Papers for Class 9 Maths Paper 1 25
CBSE Sample Papers for Class 9 Maths Paper 1 25.1

Solution 26.
(i) Draw EF || AB || CD
CBSE Sample Papers for Class 9 Maths Paper 1 26
=> ∠1 + ∠2 = x°
Now AB || EF and AE is transversal.
∠1 + ∠BAE = ∠1 + 104° = 180°
(co interior angles)
∠1 = 180°- 104° = 76°
Again EF || CD and EC is the transversal
∠2 + ∠ECD = ∠2 + 116° = 180°
=> ∠2 = 64°
Hence x = ∠1 + ∠2 = 76° + 64° = 140°
=> x = 140°
(ii) Draw EO || AB || CD
CBSE Sample Papers for Class 9 Maths Paper 1 26.1
x° = ∠1 + ∠2
Now EO || AB and OB is transversal
∠1 + ∠ABO = 180° [Co-interior angles]
∠1 + 40°= 180°
=> ∠1 = 180°- 40° = 140° => ∠1 = 140°
Again EO || CD and DO is transversal
∠2 + ∠CDO = 180°[Co-interior angles]
∠2 + 35° = 180°
=> ∠2 = 180° – 35° = 145°
=> ∠2 = 145°
∠1 + ∠2 = (140° + 145°) = 285°
=> x = ∠1 + ∠2 = 285°
=> x = 285°

Solution 27.
Linear equation 3x + 2y = 12
CBSE Sample Papers for Class 9 Maths Paper 1 27
The point A(4, 0) cuts on the x-axis and point B(0, 6) cuts on the y-axis.

Solution 28.
CBSE Sample Papers for Class 9 Maths Paper 1 28
Volume of the water running into the sea per minute
= Volume of cuboid
= l x bx h
= 50 x 45 x 2
= 4500 m3
(i) We should preserve the water and other natural resources for ourself and for our next generation because they can not be polluted or finished very fast.
(ii) Method of restoring fresh water is by ‘rain water harvesting’ in home.
(iii) Our rivers are very polluted and causing the problems in ecosystem and becoming the shortage of fresh water at large scale. So, it is necessary to clean all rivers of our country.

Solution 29.
Mean of first 13 observations = 32
Sum of the first 13 observations = 32 x 13 = 416
Mean of last 13 observations =39
Sum of last 13 observations = 39 x 13 = 507
Mean of 25 observations = 36
Sum of all the 25 observations = 36 x 25 = 900
∴ the 13th observation = (416 + 507 – 900) = 23
Hence the 13th observation = 23

Solution 30.
CBSE Sample Papers for Class 9 Maths Paper 1 30
From Graph:
BC = CE + BE = (4 – 0) + (0 – (-2))
Base = BC = 4 – (-2) = 4 + 2 = 6 units
Height = AD = OF – OE = 5 – 2 = 3 units
ar (∆ ABC) = \(\frac { 1 }{ 2 }\) x Base x height
= \(\frac { 1 }{ 2 }\) x 6 x 3 = \(\frac { 18 }{ 2 }\) = 9 sq units
ar (∆ ABC) = 9 sq. units.

We hope the CBSE Sample Papers for Class 9 Maths Paper 1 help you. If you have any query regarding CBSE Sample Papers for Class 9 Maths Paper 1, drop a comment below and we will get back to you at the earliest.

 

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 14
Chapter Name Statistics
Exercise Ex 14.4
Number of Questions Solved 6
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4

Question 1.
The following number of goals were scored by a team in a series of 10 matches
2, 3, 4, 5, 0, 1, 3, 3, 4, 3.
Find the mean, median and mode of these scores.
Solution:
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 1
(iii) Mode Arranging the given data in ascending order, we have 0, 1,2, 3, 3, 3, 3, 4, 4, 5.
Here, 3 occurs most frequently (4 times)
∴ Mode = 3

Question 2.
In a mathematics test given to 15 students, the following marks (out of 100) are recorded
41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60
Find the mean, median and mode of this data.
Solution:
(i) Mean
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 2
(ii) Median Arranging the given data in descending order, we have 98, 96, 62, 60, 54, 52, 52, 52, 48, 46, 42, 41,40, 40, 39
Number of observations (n) = 15 which is odd.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 3
(iii) Mode Arranging the data in descending order, we have 98, 96, 62, 60, 54, 52, 52, 52, 48, 46, 42, 41,40, 40, 39.
Here, 52 occurs most frequently (3 times).
∴ Mode = 52

Question 3.
The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x.
29, 32, 48, 50, x, x + 2, 72, 78, 84, 95
Solution:
Number of observations (n) = 10which is even.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 4
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 5
According to question, median = 63
∴ x + 1 = 63 ⇒ x = 63 – 1 = 62
Hence, the value of x is 62.

Question 4.
Find the mode of 14, 25,14, 28,18,17,18,14, 23, 22,14 and 18.
Solution:
The given data is,
14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18
Arranging the data in ascending order, we have
14, 14, 14, 14, 17, 18, 18, 18, 22, 23, 25, 28
Here, 14 occurs most frequently (4 times).
∴ Mode = 14

Question 5.
Find the mean salary of 60 workers of a factory from the following table
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 6
Solution:
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 7
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 img 8
Hence, the mean salary is ₹ 5083.33.

Question 6.
Give one example of a situation in which
(i) the mean is an appropriate measure of central tendency.
(ii) the mean is not an appropriate measure of central tendency but the median is an appropriate measure of central tendency.
Solution:
(i) Mean marks in a test in mathematics,
(ii) Average beauty

We hope the NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4 help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.4, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 14
Chapter Name Statistics
Exercise Ex 14.3
Number of Questions Solved 9
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3

Question 1.
A survey conducted by an organisation for the cause of illness and death among the women between the ages 15-44 (in years) worldwide, found the following figures (in %)
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 1
(i) Represent the information given above graphically.
(ii) Which condition is the major cause of women’s ill health and death worldwide?
(iii) Try to find out, with the help of your teacher, any two factors which play a major role in the cause in (ii) above being the major cause.
Solution:
(i) We draw the bar graph of this data in the following steps. Note that, the unit in the second column is percentage.

  1. We represent the causes (variable) on the horizontal axis choosing any scale, since width of the bar is not important but for clarity, we take equal widths for all bars and maintain equal gaps in between. Let on cause be represented by one unit.
  2. We represent the female fatality rate (value) on the vertical axis. Here, we can choose the scale as 1 unit = 4%.
  3. To represent our first cause i.e, reproductive health conditions, we draw & rectangle bar with width 1 unit and height 31.8 units.
  4. Similarly, other heads are represented leaving a gap of 1 unit in between two consecutive bars.

Now the graph is drawn in figure.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 2
(ii) From graph, we observe that ‘reproductive health conditions’ is the major cause of women’s ill health and death world wide because it has maximum percentage among the causes i.e.,31.8%.

Question 2.
The following data on the number of girls (to the nearest ten) per thousand boys in different sections of Indian society is given below
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 3
(i) Represent the information above by a bar graph.
(ii) In the classroom discuss, what conclusions can be arrived at from the graph.
Solution:
(i) We draw the bar graph of this data, note that the unit in the second column is number of girls per thousand boys.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 4
We represent the section on the horizontal axis choosing any scale, since width of the bar is not important but for clarity, we take equd widths for all bars and maintain equal gaps in between. Let on section be represented by one unit.
We represent the number of girls per thousand boys on the vertical axis.
Now, the graph is drawn in figure.
We represent the number of girls per thousand boys on the vertical axis. Here, we can choose the scale as 1 unit = 100.
Now, the graph is drawn in figure

(ii) From graph, we observe that scheduled tribe (ST) number of girls is major section in different sections of Indian society, because it has maximum number of girls per thousand boys i.e., 970.

Question 3.
Given below are the seats won by different political parties in the polling outcome of a state assembly elections
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 5
(i) Draw a bar graph to represent the polling results.
(ii) Which political party won the maximum number of seats?
Solution:
We draw the bar graph of this data, note that the unit in the second column is seats won by political party.
(i) We represent the political party on the horizontal axis choosing any scale, since width of the bar is not important but for clarity, we take equal widths for all bars and maintain equal gaps in between. Let on political party be represented by one unit.
(ii) We represent the seats won on the vertical axis. Here, we can choose the scale as 1 unit = 10
Now, the graph is drawn in figure
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 6
Party ‘A’ Won the maximum number of seats. i.e, 75.

Question 4.
The length of 40 leaves of a plant measured correct to one millimetre and the obtained data is represented in the following table
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 7
(i) Draw a histogram to represent the given data.
(ii) Is there any other suitable graphical representation for the same data?
(iii) Is it correct to conclude that the maximum number of leaves 153 mm long and Why?
Solution:
(i) We know that, the areas of the rectangles are proportional to the frequencies in a histogram. Now, we get the following modified table by given data
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 8
Now, we draw the histogram for given data
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 9
(ii) Frequency polygon.
(iii) No, because the maximum number of leaves have their lengths lying in
the interval 145-153.

Question 5.
The following table gives the lifetimes of 400 neon lamps
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 10
(i) Represent the given information with the help of a histogram.
(ii) How many lamps have a lifetime of more 700 h?
Solution:
(i) Here, we will make a modified table by given data.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 11
Now, we draw the histogram for above table
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 12
(ii) 184 lamps have a life time of more than 700 h i.e.,74 + 62 + 48 = 184.

Question 6.
The following table gives the distribution of students of two sections according to the marks obtained by them
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 13
Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.
Solution:
Here, we make modified tables by given data.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 14
Now, required frequency polygon curves are
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 15

Question 7.
The runs scored by two teams A and B on the first 60 balls in a cricket match are given below
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 16
Represent the data of both the teams on the same graph by frequency polygons.
Solution:
First make the class intervals continuous.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 17
Now, draw a frequency polygon curve
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 18

Question 8.
A random survey of the number of children of various age groups playing in a park was found as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 19
Draw a histogram to represent the data above.
Solution:
We know that, the areas of the rectangles are proportional to the frequencies in a histogram. Here, the widths of the rectangles are varying. So, we need to make certain modifications in the lengths of the rectangles, so that the areas are again proportional to the frequencies.

  1. Select a class interval with the minimum class size. The minimum class size is 1.
  2. The lengths of the rectangles are then modified to be proportionate to the class size

Now, we get the following table
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 20
So, the correct histogram with varying width is given below.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 21

Question 9.
100 surnames were randomly picked up from a local telephone directory and a frequency distribution of the number of letters in the English alphabet in the surnames was found as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 22
(i) Draw a histogram to depict the given information.
(ii) Write the class interval in which the maximum number of surnames lie.
Solution:
(i) We know that, the areas of the rectangles are proportional to the frequencies in a histogram. Here, the widths of the rectangles are varying. So, we need to make certain modifications in the lengths of the rectangles. So that the areas are again proportional to the frequencies.

  1. Select a class interval with the minimum class size. The minimum class size is 2.
  2. The lengths of the rectangles are then modified to be proportionate to the class size 2.

Since we have calculated these lengths for interval of 2 letters in each case, we may call these lengths as ‘proportion of surnames per 2 mark ‘ interval’.
So, the correct histogram with varying width is given below.
Here, we make a modified table by given data with minimum class size 2.
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 23
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 img 24
(ii) The class interval in which the maximum number of surnames lie is 6-8.

We hope the NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3 help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.3, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 are part of NCERT Solutions for Class 9 Maths. Here we have given NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2.

Board CBSE
Textbook NCERT
Class Class 9
Subject Maths
Chapter Chapter 14
Chapter Name Statistics
Exercise Ex 14.2
Number of Questions Solved 9
Category NCERT Solutions

NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2

Question 1.
The blood groups of 30 students of class VIII are recorded as follows
A, B, 0, 0, AB, 0, A, 0, B, A, 0, B, A, 0, 0,
A, AB, 0, A, A, 0, 0, AB, B, A, 0, B, A, B, 0
Represent this data in the form of a frequency distribution table. Which is the most common and which is the rarest blood group among these students?
Solution:
The number of students who have a certain type of blood group is called the frequency of those blood groups. To make data more easily undrestandable, we write it in a table, as given below
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 1
From table, we observe that the higher frequency blood group i.e., most common blood group is O and the lowest frequency blood group i.e., rarest blood group is AB.

Question 2.
The distance (in km) of 40 engineers from their residence to their place of work were found as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 2
Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 0-5 (5 not included). What main features do you observe from this tabular representation?
Solution:
To present such a large amount of data, so that a reader can make sense of it easily, we condense it into groups like 0-5, 5-10,…. 30-35 (since, our data is from 5 to 32). These grouping are called ‘classes’ or ‘class-intervals’ and their size is called the class size or class width which is 5 in this case. In each of these classes, the least number is called the iower class limit and the greatest number is called the upper class limit, e.g., in 0-5, 0 is the ‘lower class limit’ and 5 is the‘upper class limit’.
Now, using tally marks, the data (given) can be condensed in tabular form as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 3
Presenting data in this form simplifies and condenses data and enables us to observe certain important feature at a glance. This is called a grouped frequency distribution table. We observe that the classes in the table above are non-overlapping.

Question 3.
The relative humidity (in %) of a certain city for a month of 30 days was as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 4
(i) Construct a grouped frequency distribution table with classes 84-86, 86-88 etc.
(ii) Which month or season do you think this data is about?
(iii) What is the range of this data?
Solution:
(i) We condense the given data into groups like 84 – 86, 86 – 88, 98-100. (since, our data is from 86.5 to 99.2) the class width in this case is 2. Now, the given data can be condensed in tabular form as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 5
(ii) From table, we observe that the data appears to be taken in the rainy season as the relative humidity is high.
(iii) We know that, Range = Upper limit of data – Lower limit of data
∴ Range = 99.2 – 84.9 =14.3

Question 4.
The heights of 50 students, measured to the nearest centimeters have been found to be as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 6
(i) Represent the data given above by a grouped frequency distribution table, taking class intervals as 160-165, 165-170 etc.
(ii) What can you conclude about their heights form the table?
Solution:
(i) We condense the given data into groups like 150-155, 155-160, …,170-175. (since, our data is from 150 to 172) The class width in this case is 5.
Now, the given data can be condensed in tabular form as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 7
(ii) From the table, our conclusion is that more than 50% of students (i.e.,12 + 9+ 14 = 35) are shorter than 165 cm.

Question 5.
A study was conducted to find out the concentration of sulphur dioxide in the air in parts per million (ppm) of a certain city. The data obtained for 30 days is as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 8
(i) Make a grouped frequency distribution table for this data with class intervals as 0.00-0.04, 0.04-0.08 and so on.
(ii) For how many day’s was the the concentration of sulphur dioxide more than 0.11 parts per million (ppm)?
Solution:
(i) We condense the given data into groups like 0.00-0.04, 0. 04-0.08,…, 0.20-0.24. (since, our data is from 0.01 to 0.22). The class width in this case is 0.04.
Now, the given data can be condensed in tabular form as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 9
(ii) The concentration of sulphur dioxide was more than 0.11 ppm for 2 + 4 + 2 = 8 days (by table).

Question 6.
Three coins were tossed 30 times simultaneously. Each time the number of heads occurring was noted down as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 10
Prepare a frequency distribution table for the data given above.
Solution:
Firstly, we write the data in a table
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 11
In above table, we observe that the repeatition of ‘0’ in given data is 6 times, 1 as to 10 times, 2 as 9 times and 3 as 5 times. Also, the above table is called an ungrouped frequency distribution table or simply a frequency distribution table.

Question 7.
The value of π upto 50 decimal places is given below
3.14159265358979323846264338327950288419716939937510
(i) Make a frequency distribution of the digits from 0 to 9 after the decimal point.
(ii) What are the most and the least frequently occurring digits?
Solution:
Firstly, we write the data i.e., digits from 0 to 9 after the decimal point in a table below
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 12
(i) From the table, we observe that the digit’s after the decimal points i.e., 0,1, 2, 3, 4, 5, 6, 7, 8, 9 repeated 2, 5, 5, 8, 4, 5, 4, 4, 5, 8 times, respectively.
(ii) From the table, we observe that the digits after the decimal point 3 and 9 are most frequently occurring i.e„ 8 times. The digit ‘0’ is the least occurring i.e., only 2 times.

Question 8.
Thirty children were asked about the number of hours they watched TV programmes in the previous week.
The results were found as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 13
(i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5-10.
(ii) How many children watched television for 15 or more hours a week?
Solution:
(i) We condense the given data into groups like 0-5, 5-10 15-20.
(since, our data is from 1 to 17). The class width in this case is 5.
Now, the given data can be condensed in tabular form as follow
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 14
(ii) From table, we observe that the number of children is 2, who watched television for 15 or more hours a week.

Question 9.
A company manufactures car batteries of a particular type. The lives (in years) of 40 such batteries were recorded as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 15
Construct a grouped frequency distribution table for this data, using class intervals of size 0.5 starting from the interval 2-2.5.
Solution:
We condense the given data into groups like 2.0-2.5, 2.5-3.0 ,4.5- 5.0. (since, our data is from 2.2 to 4.6). The class width in this case is 5.
Now, the given data can be condensed in tabular form as follows
NCERT Solutions for Class 9 Maths Chapter 14 Statistics Ex 14.2 img 16
The above table is called a grouped frequency distribution table.

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