RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D

RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 6 Operations on Algebraic Expressions Ex 6D.

Other Exercises

Question 1.
Solution:
(i)(x + 6)(x + 6)
= (x + 6)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 1.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 1.2

You can also Download NCERT Solutions for Class 8 English to help you to revise complete Syllabus and score more marks in your examinations.

Question 2.
Solution:
(i) (x – 4)(x – 4)
= (x – 4)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 2.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 2.2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 2.3

Question 3.
Solution:
(i)(8a + 3b)2
= (8a)2 + 2 x 8a x 3b + (3b)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 3.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 3.2

Question 4.
Solution:
(i)(x + 3)(x – 3)
= (x)2 – (3)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 4.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 4.2

Question 5.
Solution:
(i) (54)2
= (50 + 4)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 5.1

Question 6.
Solution:
(i) (69)2
= (70 – 1)2
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 6.1

Question 7.
Solution:
(i)(82)2 – (18)2
= (82 – 18)(82 – 18)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 7.1

Question 8.
Solution:
9x2 + 24x + 16
= (3x)2 + 2 x 3x x 4 + (4)2
= (3x + 4)2
= (3 x 12 + 4)2
= (36 + 4)2
= (40)2
= 1600 Ans.

Question 9.
Solution:
64x2 + 81y2 + 144xy = (8x)2 + (9y)2 + 2 x 8x x 9y
= (8x + 9y)2
= \({ \left( 8\times 11+9\times \frac { 4 }{ 3 } \right) }^{ 2 }\)
= (88 + 12)2
= (100)2
= 10000 Ans.

Question 10.
Solution:
(36x2 + 25y2 – 60xy)
= (6x)2 + (5y)2 – 2 x 6x x 5y
= (6x – 5y)2
= \({ \left( 6\times \frac { 2 }{ 3 } -5\times \frac { 1 }{ 5 } \right) }^{ 2 } \)
= (4 – 1)2
= (3)2 = 9

Question 11.
Solution:
\(\left( x+\frac { 1 }{ 4 } \right) =4 \)
Squaring on both sides
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 11.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 11.2

Question 12.
Solution:
\(\left( x-\frac { 1 }{ x } \right) =5 \)
(i) Squaring on both sides
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 12.1
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6D 12.2

Question 13.
Solution:
(i) (x + 1) (x – 1) (x2 + 1)
= {(x)2 – (1)2} (x2 + 1)
= (x2 – 1) (x2 + 1)
= (x2)2 – (1)2 = x4 – 1 Ans.
(ii) (x – 3) (x + 3) (x2 + 9)
= {(x)2 – (3)2 } (x2 + 9)
= (x2 – 9) (x2 + 9)
= (x2)2 – (9)2 = x4 – 81 Ans.
(iii) (3x – 2y) (3x + 2y) (9x2 + 4y2)
= {(3x)2 – (2y)2} (9x2 + 4y2)
= (9x2 – 4y2) (9x2 + 4y2)
= (9x2)2 – (4y2)2
= 81x4 – 16y4 Ans.
(iv) (2p + 3) (2p – 3) (4p2 + 9)
= {(2p)2 – (3)2} (4p2 + 9)
= (4p2 – 9) (4p2 + 9)
= (4p2)2 – (9)2 = 16p4 – 81 Ans.

Question 14.
Solution:
x + y = 12
Squaring both sides,
(x + y)2 = (12)2
=> x2 + y2 + 2xy = 144
=> x2 + y2 + 2 x 14 = 144
=> x2 + y2 + 28 = 144
=> x2 + y2 = 144 – 28 = 116
x2 + y2 = 116 Ans.

Question 15.
Solution:
x – y = 7
Squaring both sides,
(x – y)2 = (7)2
=> x2 + y2 – 2xy = 49
=> x2 + y2 – 2 x 9 = 49
=> x2 + y2 – 18 = 49
=> x2 + y2 = 49 + 18 = 67
x2 + y2 = 67 Ans.

Hope given RS Aggarwal Solutions Class 8 Chapter 6 Operations on Algebraic Expressions Ex 6D are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B

RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 6 Operations on Algebraic Expressions Ex 6B.

Other Exercises

Find each of the following products?

Question 1.
Solution:
(5x + 7) X (3x + 4) = 5x(3x + 4) + 7(3x + 4)
= 15x2 + 20x + 21x + 28 = 15x2 + 41x + 28 Ans.

Question 2.
Solution:
(4x + 9) X (x – 6) = 4x(x – 6) + 9(x – 6)
= 4x2 – 24x + 9x – 54
= 4x2 – 15x – 54 Ans.

Question 3.
Solution:
(2x + 5) X (4x – 3) = 2x(4x – 3) + 5(4x – 3)
= 8x2 – 6x + 20x – 15
= 8x2 + 14x – 15 Ans.

Question 4.
Solution:
(3y – 8) X (5y – 1) = 3y(5y – 1) – 8(5y – 1)
= 15y2 – 3y – 40y + 8
= 15y2 – 43y + 8 Ans.

Question 5.
Solution:
(7x + 2y) X (x + 4y)
= 7x(x + 4y) + 2y(x + 4y)
= 7x2 + 28xy + 2xy + 8y2
= 7x2 + 30xy + 8y2 Ans.

Question 6.
Solution:
(9x + 5y) X (4x + 3y) = 9x(4x + 3y) + 5y(4x + 3y)
= 36x2 + 27xy + 20xy + 15y2
= 36x2 + 47xy + 15y2 Ans.

Question 7.
Solution:
(3m – 4n) X (2m – 3n)
= 3m(2m – 3n) – 4n(2m – 3n)
= 6m2 – 9mn – 8mn + 12n2
= 6m2 – 17mn + 12n2 Ans.

Question 8.
Solution:
(x2 – a2) X (x – a)
= x2(x – a) – a2(x – a)
= x3 – x2a – xa2 + a3 Ans.

Question 9.
Solution:
(x2 – y2) X (x + 2y)
= x2(x + 2y) – y2(x + 2y)
= x3 + 2x2y – xy2 – 2y3 Ans.

Question 10.
Solution:
(3p2 + q2) X (2p2 – 3q2)
= 3p2(2p2 – 3q2) + q2(2p2 – 3q2)
= 6p4 – 9p2q2 + 2p2q2 – 3q4
= 6p4 – 7p2q2 – 3q4 Ans.

Question 11.
Solution:
(2x2 – 5y2) X (x2 + 3y2)
= 2x2(x2 + 3y2) – 5y2(x2 + 3y2)
= 2x4 + 6x2y2 – 5x2y2 – 15y4)
= 2x4 + x2y2 – 15y4 Ans.

Question 12.
Solution:
(x3 – y3) X (x2 + y2)
= x3(x2 + y2) – y3(x2 + y2)
= x5 + x3y2 – x2y3 – y5 Ans.

Question 13.
Solution:
(x4 + y4) X (x2 – y2)
= x4(x2 – y2) + y4(x2 – y2)
= x6 – x4y2 + x2y4 – y6 Ans.

Question 14.
Solution:
\(\left( { x }^{ 4 }+\frac { 1 }{ { x }^{ 4 } } \right) \times \left( { x+ }\frac { 1 }{ { x } } \right)\)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B 14.1

Find each of the following products:

Question 15.
Solution:
(x2 – 3x + 7) X (2x + 3)
= (x2 – 3x + 7) (2x) + (x2 – 3x + 7) X 3
= 2x3 – 6x + 14x + 3x2 – 9x + 21
= 2x3 – 3x2 + 5x + 21 Ans.

Question 16.
Solution:
(3x2 + 5x – 9) X (3x – 5)
= 3x2(3x – 5x) + 5x(3x – 5) – 9(3x – 5)
= 9x3 – 15x2 + 15x2 – 25x – 27x + 45
= 9x3 – 52x + 45 Ans.

Question 17.
Solution:
(x2 – xy + y2) X (x + y)
= (x2 – xy + y2) X x + (x2 – xy + y2) X y
= x3 – x2y + xy2 + x2y – xy2 + y3
= x3 + y3 Ans.

Question 18.
Solution:
(x2 + xy + y2) X (x – y)
(x2 + xy + y2) X x + (x2 + xy + y2) X ( – y)
= x3 + x2y + xy2 – x2y – xy2 – y3
= x3 – y3 Ans.

Question 19.
Solution:
(x3 – 2x2 + 5) X (4x – 1)
= (x3 – 2x2 + 5) X 4x + (x3 – 2x2 + 5) X ( – 1)
= 4x4 – 8x3 + 20x – x3 + 2x2 – 5
= 4x4 – 9x3 + 2x2 + 20x – 5 Ans.

Question 20.
Solution:
(9x2 – x + 15) X (x2 – 3)
(9x2 – X + 15) X x2 + (9x2 – x + 15) X ( – 3)
= 9x4 – x3 + 15x2 – 27x2 + 3x – 45
= 9x4 – x3 – 12x2 + 3x – 45 Ans.

Question 21.
Solution:
(x2 – 5x + 8) X (x2 + 2)
= (x2 – 5x + 8) X x2 + (x2 – 5x + 8) X 2
= x4 – 5x3 + 8x2 + 2x2 – 10x + 16
= x4 – 5x3 + 10x2 – 10x + 16 Ans.

Question 22.
Solution:
(x3 – 5x2 + 3x + 1) X (x2 – 3)
= (x3 – 5x2 + 3x + 1) X x2 + (x3 – 5x2 + 3x + 1) X ( – 3)
= x5 – 5x4 + 3x3 + x2 – 3x3 + 15x2 – 9x – 3
= x5 – 5x4 + 16x2 – 9x – 3 Ans.

Question 23.
Solution:
(3x + 2y – 4) X (x – y + 2)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B 23.1

Question 24.
Solution:
(x2 – 5x + 8) X (x2 + 2x – 3)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B 24.1

Question 25.
Solution:
(2x2 + 3x – 7) X (3x2 – 5x + 4)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B 25.1

Question 26.
Solution:
(9x2 – x + 15) X (x2 – x – 1)
RS Aggarwal Class 8 Solutions Chapter 6 Operations on Algebraic Expressions Ex 6B 26.1

Hope given RS Aggarwal Solutions Class 8 Chapter 6 Operations on Algebraic Expressions Ex 6B are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C

RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 4 Cubes and Cube Roots Ex 4C.

Other Exercises

Evaluate:

Question 1.
Solution:
\(\sqrt [ 3 ]{ 64 } \)
= \(\sqrt [ 3 ]{ 4X4X4 } \)
= \(\sqrt [ 3 ]{ { 4 }^{ 3 } } \)
= 4

Question 2.
Solution:
\(\sqrt [ 3 ]{ 343 } \)
= \(\sqrt [ 3 ]{ 7X7X7 } \)
= \(\sqrt [ 3 ]{ { 7 }^{ 3 } } \)
= 7

Question 3.
Solution:
\(\sqrt [ 3 ]{ 729 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q3.1

Question 4.
Solution:
\(\sqrt [ 3 ]{ 1728 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q4.1

Question 5.
Solution:
\(\sqrt [ 3 ]{ 9261 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q5.1

Question 6.
Solution:
\(\sqrt [ 3 ]{ 4096 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q6.1

Question 7.
Solution:
\(\sqrt [ 3 ]{ 8000 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q7.1

Question 8.
Solution:
\(\sqrt [ 3 ]{ 3375 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q8.1

Question 9.
Solution:
\(\sqrt [ 3 ]{ -216 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q9.1

Question 10.
Solution:
\(\sqrt [ 3 ]{ -512 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q10.1

Question 11.
Solution:
\(\sqrt [ 3 ]{ -1331 } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q11.1

Question 12.
Solution:
\(\sqrt [ 3 ]{ \frac { 27 }{ 64 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q12.1

Question 13.
Solution:
\(\sqrt [ 3 ]{ \frac { 125 }{ 216 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q13.1

Question 14.
Solution:
\(\sqrt [ 3 ]{ \frac { -27 }{ 125 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q14.1

Question 15.
Solution:
\(\sqrt [ 3 ]{ \frac { -64 }{ 343 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q15.1

Question 16.
Solution:
\(\sqrt [ 3 ]{ 64\times 729 }\)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q16.1

Question 17.
Solution:
\(\sqrt [ 3 ]{ \frac { 729 }{ 1000 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q17.1

Question 18.
Solution:
\(\sqrt [ 3 ]{ \frac { -512 }{ 343 } } \)
RS Aggarwal Class 8 Solutions Chapter 4 Cubes and Cube Roots Ex 4C Q18.1

Hope given RS Aggarwal Solutions Class 8 Chapter 4 Cubes and Cube Roots Ex 4C are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RS Aggarwal Class 8 Solutions Chapter 7 Factorisation Ex 7B

RS Aggarwal Class 8 Solutions Chapter 7 Factorisation Ex 7B

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7B.

Other Exercises

Question 1.
Solution:
x2 – 36
= (x)2 – (6)2 { ∵ a2 – b2 = (a + b) (a – b)}
= (x + 6) (x – 6) Ans.

Question 2.
Solution:
4a2 – 9
= (2a)2 – (3)2
= (2a + 3) (2a – 3)
{ ∵ a2 – b2 = (a + b) (a – b)}

You can also Download NCERT Solutions for Class 8 English to help you to revise complete Syllabus and score more marks in your examinations.

Question 3.
Solution:
81 – 49x2
= (9)2 – (7x)2
= (9 + 7x) (9 – 7x) { ∵ a2 – b2 = (a + b) (a – b)}

Question 4.
Solution:
= (2x)2 – (3y)2
= (2x + 3y)(2x-3y)
{∵ a2 – b2 = (a + b) (a – b)}

Question 5.
Solution:
Using a2 – b2
= (a + b) (a – b)
= 16a2 – 225b2
= (4a)2 – (15b)2
= (4a + 15b) (4b – 5b)

Question 6.
Solution:
Using a2 – b2
= (a + b) (a – b)
= (3ab)2 – (5)2
= (3ab + 5) (3ab – 5)

Question 7.
Solution:
Using a2 – b2 = (a + b) (a – b)
16a2 – 144 = (4a)2 = (12)2
= (4a + 12) (4a – 12)
= 4 (a + 3) x 4 (a – 3)
= 16 (a + 3) (a – 3)

Question 8.
Solution:
63a2 – 112b2
= 7 (9a2 – 16b2)
= 7 [(3a)2 – (4b)2
= 7 (3a + 4b) (3a – 4b)

Question 9.
Solution:
20a2 – 45b2
= 5 {4a2 – 9b2}
= 5{(2a)2 – (3b)2)
= 5(2a + 3b) (2a – 3b) Ans.

Question 10.
Solution:
12x2 – 27
= 3(4x2 – 9)
= 3{(2x)2 – (3)2}
= 3(2x + 3) (2x – 3) Ans.

Question 11.
Solution:
x3 – 64x
= x(x2 – 64)
= x{(x)2 – (8)2}
= x(x + 8) (x – 8) Ans.

Question 12.
Solution:
16x5 – 144x3
= 16x3 [x2 – 9]
= 16x3 [(x)2 – (3)2]
= 16x3 (x + 3) (x – 3)

Question 13.
Solution:
3x5 – 48x3
= 3x3 {x2 – 16}
= 3x3{(x)2 – (4)2}
= 3x3 (x + 4) (x – 4) Ans.

Question 14.
Solution:
16p3 – 4p
= 4p [4p2 – 1]
= 4p ((2p)2 – (1)2]
= 4p(2p + 1)(2p – 1)

Question 15.
Solution:
63a2b2 – 7
= 7(9a2b2 – 1)
= 7{(3ab)2 – (1)2)
= 7(3ab + 1) (3ab – 1) Ans.

Question 16.
Solution:
1 – (b – c)2
= (1)2 – (b – c)2
= (1 + b + c) (1 – b + c) Ans.
{ ∵ a2 – b2 = (a + b) (a – b)}

Question 17.
Solution:
(2a + 3b)2 – 16c2
= (2a + 3b)2 – (4c)2
=(2a + 3b + 4c)(2a + 3b – 4c)Ans.
{ ∵ a2 – b2 = (a + b)(a – b)}

Question 18.
Solution:
(l + m)2 – (l – m)2
= (l + m + l – m)(l + m – l + m)
{ ∵ a2 – b2 = (a + b)(a – b)}
= 2l x 2m = 4lm

Question 19.
Solution:
(2x + 5y)2 – (1)2
=(2x + 5y + 1)(2x + 5y – 1)
{ ∵ a2 – b2 = (a + b)(a – b)}

Question 20.
Solution:
36c2 – (5a + b)2
= (6c)2 – (5a + b)2
{ ∵ a2 – b2 = (a + b)(a – b)}
= (6c + 5a + b)(6c – 5a – b)

Question 21.
Solution:
(3x – 4y)2 – 25z2
= (3x – 4y)2 – (5z)2
= (3x – 4y + 5z) (3x – 4y – 5z) Ans.

Question 22.
Solution:
x2 – y2 – 2y – 1
= x2 – (y2 + 2y + 1)
= (x)2 – (y + 1)2
= (x + y + 1)(x – y – 1)Ans.

Question 23.
Solution:
25 – a2 – b2 – 2ab
= 25 – (a2 + b2 + 2ab)
= (5)2 – (a + b)2
= (5 + a + b)(5 – a – b)Ans.

Question 24.
Solution:
25a2 – 4b2 + 28bc – 49c2
= 25a2 – [4b2 – 28bc + 49c2]
{ ∵ a2 – 2ab + b2 = (a – b)2}
= (5a)2 – [(2b)2 – 2 x 2b x 7c + (7c)2]
= (5a)2 – (2b – 7c)2
{ ∵ (a2 – b2 = (a + b)(a – b)}
= (5a + 2b – 7c) (5a – 2b + 7c)

Question 25.
Solution:
9a2 – b2 + 4b – 4
= 9a2 – (b2 – 4b + 4)
= (3a)2 – [(b)2 – 2 x b x 2 + (2)2]
= (3a)2 – (b – 2)2
{ ∵ a2 – 2ab + b2 = (a – b)2}
= (3a + b – 2)(3a – b + 2)
{ ∵ a2 – b2 = (a + b)(a – b)}

Question 26.
Solution:
(10)2 – (x – 5)2
= (10)2 – (x – 5)2
= (10 + x – 5)(10 – x + 5)
= (5 + x) (15 – x) Ans.

Question 27.
Solution:
{(405)2 – (395)2}
= (405)2 – (395)2
= (405 + 395) (405 – 395)
{ ∵ a2 – b2(a + b) (a – b)}
= 800 x 10 = 8000

Question 28.
Solution:
(7.8)2 – (2.2)2
= (7.8 + 2.2) (7.8 – 2.2)
= 10.0 x 5.6
= 56 Ans.

Hope given RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7B are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D

RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 3 Squares and Square Roots Ex 3D.

Other Exercises

Find the square root of each of the following numbers by using the method of prime factorization:

Question 1.
Solution:
225 = 3 x 3 x 5 x 5
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q1.1

Question 2.
Solution:
441 = 3 x 3 x 7 x 7
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q2.1

Question 3.
Solution:
729 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q3.1

Question 4.
Solution:
1296 = 2 x 2 x 2 x 2 x 3 x 3 x 3 x 3
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q4.1

Question 5.
Solution:
2025 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q5.1

Question 6.
Solution:
4096 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q6.1

Question 7.
Solution:
7056 = 2 x 2 x 2 x 2 x 3 x 3 x 7 x 7
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q7.1

Question 8.
Solution:
8100 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q8.1

Question 9.
Solution:
9216 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q9.1

Question 10.
Solution:
11025 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q10.1

Question 11.
Solution:
15876 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q11.1

Question 12.
Solution:
17424 =
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q12.1

Question 13.
Solution:
Factorizing 252, we get :
252 = \(\overline { 2X2 } X\overline { 3X3 } X7\)
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q13.1
To make it is a perfect square it must by multiplied by 7.
Square root of 252 x 7 = 1764
= 2 x 3 x 7 = 42 Ans.

Question 14.
Solution:
Factorizing 2925, we get :
2925 = \(\overline { 3X3 } X\overline { 5X5 } X13\)
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q14.1
To make it a perfect square it must be divided by 13.
2925 ÷ 13 = 225
Square root of 225 = 3 x 5 = 15 Ans.

Question 15.
Solution:
Let no. of rows = x
Then the number of plants in each row = x
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q15.1
Hence no. of rows = 35
and no. of plants in each row = 35

Question 16.
Solution:
Let no. of students in the class = x
Then contribution of each student = x
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q16.1
No. of students of the class = 34 Ans.

Question 17.
Solution:
L.C.M. of 6, 9, 15 and 20
= 2 x 3 x 5 x 2 x 3 = 180
180 = \(\overline { 2X2 } X\overline { 3X3 } X5\)
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q17.1
To make it a perfect square, it must be multiplied by 5
Product = 180 x 5 = 900
Hence, the least square number = 900 Ans.

Question 18.
Solution:
L.C.M. of 8, 12, 15, 20 = 2 x 2 x 2 x 3 x 5= 120
120 = \(\overline { 2X2 }\)X2X3X5
To make it a perfect square it must be multiplied by 2 x 3 x 5 = 30
Then least perfect square = 120 x 30 = 3600
RS Aggarwal Class 8 Solutions Chapter 3 Squares and Square Roots Ex 3D Q18.1

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Value Based Questions in Science for Class 9 Chapter 15 Improvement in Food Resources

Value Based Questions in Science for Class 9 Chapter 15 Improvement in Food Resources

These Solutions are part of Value Based Questions in Science for Class 9. Here we have given Value Based Questions in Science for Class 9 Chapter 15 Improvement in Food Resources

Question 1.
Shyam has been cultivating wheat crop year after year in the same field. Recendy he has observed decline in the yield despite best inputs. Agriculture inspector of the area suggested him to sow soyabean for one or two years before again using the field for wheat crop. What is the rationale behind this suggestion ?
Answer:
Sowing the same crop in the same field year after year results in depletion of nutrients from the particular depth of the soil, growing and multiplication of soil borne pathogens and pests of the crop, growth of weeds, infections and infestations.
Growing soyabean in the field will improve soil structure and fertility as it will draw water and nutrients from different level and add nitrogen salts. Weeds, soil borne pathogens and pests of wheat crop will be eliminated as they do not find their host.

More Resources

Question 2.
Why should fumigation be preferred over spraying in godowns ?
Answer:

  1. In fumigation, the worker does not come in contact with the fumigant. There is some contact with the pesticide during spraying. In spraying, the worker suffers irritation in eyes, nose, vomiting, etc.
  2. No residue remains over articles in fumigation. In spraying some residue can enter the sprayed articles.
  3. Fumigants are volatile while sprays are seldom volatile.
  4. Fumigation disinfects the whole area. Spraying disinfects only the sprayed articles.
  5. The volume of fumigant is small while the volume of sprayed pesticide is generally large.

Question 3.
What is the need of crossing the exotic cattle with Indian cattle when exotic cattle have higher yield as compared to the hybrid cattle ?
Answer:
There is no doubt that the hybrid produced by cross breeding exotic breed with local breed yields less milk as compared to the exotic breed. However, exotic breed cannot be incorporated in our dairy farms and farm houses due to :

  1. Different climatic conditions. Most of the exotic breeds have come from colder countries. Colder areas are limited in our country.
  2. The exotic breeds will fall prey to local pests and pathogens easily as they are not resistant to them.
  3. The feed available locally does not match with the feed required by the exotic breeds.
    Therefore, there is no alternative bur to import a few exotic cattle and cross-breed them with local cattle for obtaining hybrid cattle acclimitised to local climate and resistant to local diseases.

Question 4.
Why should organic foods be preferred over conventional foods ?
Answer:
The conventional foods are raised using chemical fertilizers and chemical pesticides. These agrochemicals pass into conventional foods in small traces. Repeated use of conventional foods increases the concentration of agrochemicals in our bodies. They become toxic. As a result a number of ailments and harms can occur to us.
On the other hand, organic foods are free from any traces ol agrochemicals as they are raised by using manures, biofertilizers and biopesticides. Being nontoxic, organic foods should be preferred over conventional foods. Agrochemicals used in raising conventional foods are highly pollutants. They pollute soil, ground water and surface waters. Eutrophication of ponds and lakes is due to them. Manure used in raising organic foods is environmentally clean method of disposing off and recycling organic wastes.

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RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C

RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C

These Solutions are part of RS Aggarwal Solutions Class 10. Here we have given RS Aggarwal Solutions Class 10 Chapter 11 Arithmetic Progressions Ex 11C

Other Exercises

Question 1.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 1
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 2
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 3
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 4

Question 2.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 5
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 6
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 7
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 8
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 9

Question 3.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 10

Question 4.
Solution:
Sn = 3n² + 6n
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 11

Question 5.
Solution:
Sn = 3n² – n
S1 = 3(1)² – 1 = 3 – 1 = 2
S2 = 3(2)² – 2 = 12 – 2 = 10
T2 = 10 – 2 = 8 and
T1 = 2
(i) First term = 2
(ii) Common difference = 8 – 2 = 6
Tn = a + (n – 1) d = 2 + (n – 1) x 6
= 2 + 6n – 6 = 6n – 4

Question 6.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 12
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 13
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 14

Question 7.
Solution:
Let a be first term and d be the common difference of an AP.
Since, we have,
am = a + (m – 1) d = \(\frac { 1 }{ n }\) …(i)
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 15
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 16

Question 8.
Solution:
AP is 21, 18, 15,…
Here, a = 21,
d = 18 – 21 = -3,
sum = 0
Let number of terms be n, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 17
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 18

Question 9.
Solution:
AP is 9, 17, 25,…
Here, a = 9, d = 17 – 9 = 8
Sum of terms = 636
Let number of terms be n, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 19
Which is not possible being negative and fraction.
n = 12
Number of terms = 12

Question 10.
Solution:
AP is 63, 60, 57, 54,…
Here, a = 63, d = 60 – 63 = -3 and sum = 693
Let number of terms be n, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 20
22th term is zero.
There will be no effect on the sum.
Number of terms are 21 or 22.

Question 11.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 21
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 22
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 23

Question 12.
Solution:
Odd numbers between 0 and 50 are 1, 3, 5, 7, 9, …, 49
Here, a = 1, d = 3 – 1 = 2, l = 49
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 24
= \(\frac { 25 }{ 2 }\) x 50 = 25 x 25 = 625

Question 13.
Solution:
Numbers between 200 and 400 which are divisible by 7 will be 203, 210, 217,…, 399
Here, a = 203, d = 7, l = 399
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 25

Question 14.
Solution:
First forty positive integers are 0, 1, 2, 3, 4, …
and numbers divisible by 6 will be 6, 12, 18, 24, … to 40 terms
Here, a = 6, d = 12 – 6 = 6, n = 40 .
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 26

Question 15.
Solution:
First 15 multiples of 8 are 8, 16, 24, 32, … to 15 terms
Here, a = 8, d = 16 – 8 = 8 , n = 15
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 27

Question 16.
Solution:
Multiples of 9 lying between 300 and 700 = 306, 315, 324, 333, …, 693
Here, a = 306, d = 9, l = 693
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 28

Question 17.
Solution:
Three digit numbers are 100, 101, …, 999
and numbers divisible by 13, will be 104, 117, 130, …, 988
Here, a = 104, d = 13, l = 988
Tn (l) = a + (n – 1) d
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 29

Question 18.
Solution:
Even natural numbers are 2, 4, 6, 8, 10, …
Even natural numbers which are divisible by 5 will be
10, 20, 30, 40, … to 100 terms
Here, a = 10, d = 20 – 10 = 10, n = 100
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 30

Question 19.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 31
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 32

Question 20.
Solution:
Let a be the first term and d be the common difference of the AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 33
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 34

Question 21.
Solution:
Let a be the first term and d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 35
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 36

Question 22.
Solution:
Let a be the first term and d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 37

Question 23.
Solution:
In an AP
a = 17, d = 9, l = 350
Let number of terms be n, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 38

Question 24.
Solution:
Let a be the first term, d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 39

Question 25.
Solution:
In an AP, let a be the first term and d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 40

Question 26.
Solution:
Let a be the first term and d be the common difference of an AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 41

Question 27.
Solution:
Let a be first term and d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 42
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 43

Question 28.
Solution:
Let first term be a and d be the common difference in an AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 44
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 45

Question 29.
Solution:
Let a be the first term and d be the common difference of an AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 46
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 47

Question 30.
Solution:
Let a1 and a2 be the first terms of the two APs and d be the common difference, then
a1 = 3, a2 = 8
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 48

Question 31.
Solution:
Let a be the first term and d be the common difference, then
S10 = -150
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 49
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 50

Question 32.
Solution:
Let a be the first term and d be the common difference, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 51
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 52

Question 33.
Solution:
Let a be the first term and d be the common difference of an AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 53
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 54

Question 34.
Solution:
(i) AP is 5, 12, 19,… to 50 terms
Here, a = 5, d = 12 – 5 = 7, n = 50
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 55
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 56

Question 35.
Solution:
Let a1, a2 be the first term and d1, d2 be common difference of the two AP’s respectively.
Given, ratio of sum of first n terms =
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 57
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 58

Question 36.
Solution:
Let a be the first term and d be the common difference of an AP.
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 59
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 60

Question 37.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 61

Question 38.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 62
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 63

Question 39.
Solution:
AP is -12, -9, -6,…, 21
Here, a = -12, d = -9 – (-12) = -9 + 12 = 3, l = 21
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 64

Question 40.
Solution:
S14 = 1505
Let a be the first term and d be the common difference, then
a = 10
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 65

Question 41.
Solution:
Let a be the first term and d be the common difference of an AP, then
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 66

Question 42.
Solution:
In the school, there are 12 classes, class 1 to 12 and each class has two sections.
Each class plants double of the class
i.e. class 1 plants two plant, class 2 plants 4 plants, class 3 plants 6 plants, and so on.
So, total plants will be for each class each sections = 2 + 4 + 6 + 8 … + 24
Here, a = 2, d = 2, l = 24, n = 12
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 67
Each class has. two sections.
Plants will also be doubt
i.e. Total plants = 156 x 2 = 312

Question 43.
Solution:
In a potato race,
Bucket is at 5 m from first potato and then the distance between the two potatoes is 3m.
There are 10 potatoes.
The player, pick potato and put it in the bucket one by one.
Total distance in m to be covered, for 1st, 2nd, 3rd, … potato.
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 68

Question 44.
Solution:
Total number of trees = 25
Distance between them = 5 m in a line.
There is a water tank which is 10 m from the first tree.
A gardener waters these plants separately.
Total distance for going and coming back
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 69
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 70

Question 45.
Solution:
Total sum = ₹ 700
Number of cash prizes = 7
Each prize in ₹ 20 less than its preceding prize.
Let first prize = ₹ x
Then second prize = ₹ (x – 20)
Third prize = ₹ (x – 40) and so on.
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 71

Question 46.
Solution:
Total savings = ₹ 33000
Total period = 10 months
Each month, a man saved ₹ 100 more than its preceding of month.
Let he saves ₹ x in the first month.
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 72

Question 47.
Solution:
Total debt to be paid = ₹ 36000
No. of monthly installments = 40
After paying 30 installments, \(\frac { 1 }{ 3 }\) of his debt left
i.e. ₹ 36000 x \(\frac { 1 }{ 3 }\) = ₹ 12000
and amount paid = ₹ 36000 – ₹ 12000 = ₹ 24000
Monthly installments are in AP.
Let first installment = x
and common difference = d
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 73
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 74

Question 48.
Solution:
A contractor will pay the penalty for not doing the work in time.
For the first day = ₹ 200
For second day = ₹ 250
For third day = ₹ 300 and so on
The work was delayed for 30 days
Total penalty, he paid
200 + 250 + 300 + ….. to 30 terms
Here, a = 200, d = 50, n = 30
Total sum = \(\frac { n }{ 2 }\) [2a + (n – 1) d]
= \(\frac { 30 }{ 2 }\) [2 x 200 + (30 – 1) x 50]
= 15 [400 + 29 x 50]
= 15 [400 + 1450]
= 15 x 1850 = ₹ 27750

Question 49.
Solution:
Child will put 5 rupee on 1st day, 10 rupee (2 x 5 rupee)
on 2nd day, 15 rupee (3 x 5 rupee) on 3rd day etc.
Total saving = 190 coins = 190 x 5 = 950 rupee
The above problem can be written as Arithmetic Progression series
5, 10, 15, 20, ……
with a = 5, d = 5, Sn = 950
Let n be the last day when piggy bank become full.
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11C 75
⇒ n (n + 20) – 19 (n + 20) = 0
⇒ (n + 20) (n – 19) = 0
⇒ n + 20 = 0 or n – 19 = 0
⇒ n = -20 or n = 19
cannot be negative, hence n = 19
She can put money for 19 days.
Total saving is 950 rupees.

Hope given RS Aggarwal Solutions Class 10 Chapter 11 Arithmetic Progressions Ex 11C are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5

RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5

These Solutions are part of RD Sharma Class 9 Solutions. Here we have given RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5

Other Exercises

Question 1.
ABC is a triangle and D is the mid-point of BC. The perpendiculars from D to AB and AC are equal. Prove that the triangle is isosceles.
Solution:
Given : In ∆ABC, D is mid-point of BC and DE ⊥ AB, DF ⊥ AC and DE = DF
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q1.1
To Prove : ∆ABC is an isosceles triangle
Proof : In right ∆BDE and ∆CDF,
Side DE = DF
Hyp. BD = CD
∴ ∆BDE ≅ ∆CDF (RHS axiom)
∴ ∠B = ∠C (c.p.c.t.)
Now in ∆ABC,
∠B = ∠C (Prove)
∴ AC = AB (Sides opposite to equal angles)
∴ AABC is an isosceles triangle

Question 2.
ABC is a triangle in which BE and CF are, respectively, the perpendiculars to the sides AC and AB. If BE = CF, prove that ∆ABC is an isosceles.
Solution:
Given : In ∆ABC,
BE ⊥ AC and CF ⊥ AB
BE = CF
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q2.1
To prove : AABC is an isosceles triangle
Proof : In right ABCE and ABCF Side
BE = CF (Given)
Hyp. BC = BC (Common)
∴ ∆BCE ≅ ∆BCF (RHS axiom)
∴ ∠BCE = ∠CBF (c.p.c.t.)
∴ AB = AC (Sides opposite to equal angles)
∴ ∆ABC is an isosceles triangle

Question 3.
If perpendiculars from any point within an angle on its arms are congruent, prove that it lies on the bisector of that angle.
Solution:
Given : A point P lies in the angle ABC and PL ⊥ BA and PM ⊥ BC and PL = PM. PB is joined
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q3.1
To prove : PB is the bisector ∠ABC,
Proof : In right ∆PLB and ∆PMB
Side PL = PM (Given)
Hyp. PB = PB (Common)
∴ ∆PLB ≅ ∆PMB (RHS axiom)
∴ ∆PBL = ∆PBM (c.p.c.t.)
∴ PB is the bisector of ∠ABC

Question 4.
In the figure, AD ⊥ CD and CB ⊥ CD. If AQ = BP and DP = CQ, prove that ∠DAQ = ∠CBP.
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q4.1
Solution:
Given : In the figure,
AD ⊥ CD and CB ⊥ CD, AQ = BP and DP = CQ
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q4.2
To prove : ∠DAQ = ∠CBP
Proof : ∵ DP = CQ
∴ DP + PQ = PQ + QC
⇒ DQ = PC
Now in right ∆ADQ and ∆BCP
Side DQ = PC (Proved)
Hyp. AQ = BP
∴ ∆ADQ ≅ ∆BCP (RHS axiom)
∴ ∠DAQ = ∠CBP (c.p.c.t.)

Question 5.
Which of the following statements are true (T) and which are false (F):
(i) Sides opposite to equal angles of a triangle may be unequal.
(ii) Angles opposite to equal sides of a triangle are equal.
(iii) The measure of each angle of an equilateral triangle is 60°.
(iv) If the altitude from one vertex of a triangle bisects the opposite side, then the triangle may be isosceles.
(v) The bisectors of two equal angles of a triangle are equal.
(vi) If the bisector of the vertical angle of a triangle bisects the base, then the triangle may be isosceles.
(vii) The two altitudes corresponding to two equal sides of a triangle need not be equal.
(viii)If any two sides of a right triangle are respectively equal to two sides of other right triangle, then the two triangles are congruent.
(ix) Two right triangles are congruent if hypotenuse and a side of one triangle are respectively equal to the hypotenuse and a side of the other triangle.
Solution:
(i) False : Sides opposite to equal angles of a triangle are equal.
(ii) True.
(iii) True.
(iv) False : The triangle is an isosceles triangle.
(v) True.
(vi) False : The triangle is an isosceles.
(vii) False : The altitude an equal.
(viii) False : If one side and hypotenuse of one right triangle on one side and hypotenuse of the other right triangle are equal, then triangles are congruent.
(ix) True.

Question 6.
Fill in the blanks in the following so that each of the following statements is true.
(i) Sides opposite to equal angles of a triangle are …….
(ii) Angle opposite to equal sides of a triangle are …….
(iii) In an equilateral triangle all angles are …….
(iv) In a ∆ABC if ∠A = ∠C, then AB = …….
(v) If altitudes CE and BF of a triangle ABC are equal, then AB = ……..
(vi) In an isosceles triangle ABC with AB = AC, if BD and CE are its altitudes, then BD is ……… CE.
(vii) In right triangles ABC and DEF, if hypotenuse AB = EF and side AC = DE, then ∆ABC ≅ ∆……
Solution:
(i) Sides opposite to equal angles of a triangle are equal.
(ii) Angle opposite to equal sides of a triangle are equal.
(iii) In an equilateral triangle all angles are equal.
(iv) In a ∆ABC, if ∠A = ∠C, then AB = BC.
(v) If altitudes CE and BF of a triangle ABC are equal, then AB = AC.
(vi) In an isosceles triangle ABC with AB = AC, if BD and CE are its altitudes, then BD is equal to CE.
(vii) In right triangles ABC and DEF, it hypotenuse AB = EF and side AC = DE, then ∆ABC ≅ ∆EFD.

Question 7.
ABCD is a square, X and Y are points on sides AD and BC respectively such that AY = BX. Prove that BY = AX and ∠BAY = ∠ABX.
Solution:
Given : In square ABCD, X and Y are points on side AD and BC respectively and AY = BX
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 Q7.1
To prove : BY = AX
∠BAY = ∠ABX
Proof: In right ∆BAX and ∆ABY
AB =AB (Common)
Hyp. BX = AY (Given)
∴ ∆BAX ≅ ∆ABY (RHS axiom)
∴ AX = BY (c.p.c.t.)
∠ABX = ∠BAY (c.p.c.t.)
Hence, BY = AX and ∠BAY = ∠ABX.

Hope given RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.5 are helpful to complete your math homework.

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RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3

RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3

These Solutions are part of RD Sharma Class 9 Solutions. Here we have given RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3

Other Exercises

Question 1.
In two right triangles one side an acute angle of one are equal to the corresponding side and angle of the other. Prove that the triangles are congruent.
Solution:
Given : In ∆ABC and ∆DEF,
∠B = ∠E = 90°
∠C = ∠F
AB = DE
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q1.1
To prove : ∆ABC = ∆DEF
Proof : In ∆ABC and ∆DEF,
∠B = ∠E (Each = 90°)
∠C = ∠F (Given)
AB = DE (Given)
∆ABC = ∆DEF (AAS axiom)

Question 2.
If the bisector of the exterior vertical angle of a triangle be parallel to the base. Show that the triangle is isosceles.
Solution:
Given : In ∆ABC, AE is the bisector of vertical exterior ∠A and AE \(\parallel\) BC
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q2.1
To prove : ∆ABC is an isosceles
Proof: ∵ AE \(\parallel\) BC
∴ ∠1 = ∠B (Corresponding angles)
∠2 = ∠C (Alternate angle)
But ∠1 = ∠2 (∵ AE is the bisector of ∠CAD)
∴ ∠B = ∠C
∴ AB = AC (Sides opposite to equal angles)
∴ ∆ABC is an isosceles triangle

Question 3.
In an isosceles triangle, if the vertex angle is twice the sum of the base angles, calculate the angles of the triangle.
Solution:
Given : In ∆ABC, AB = AC
∠A = 2(∠B + ∠C)
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q3.1
To calculate: Base angles,
Let ∠B = ∠C = x
Then ∠A = 2(∠B + ∠C)
= 2(x + x) = 2 x 2x = 4x
∵ Sum of angles of a triangle = 180°
∴ 4x + x + x – 180° ⇒ 6x = 180°
⇒ x= \(\frac { { 180 }^{ \circ } }{ 6 }\)  = 30° o
∴ ∠B = ∠C = 30 and ∠A = 4 x 30° = 120

Question 4.
Prove that each angle of an equilateral triangle is 60°. [NCERT]
Solution:
Given : ∆ABC is an equilateral triangle
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q4.1
Proof: In ∆ABC,
AB = AC (Sides of an equilateral triangle)
∴ ∠C = ∠B …(i)
(Angles opposite to equal angles)
Similarly, AB = BC
∴ ∠C = ∠A …(ii)
From (i) and (ii),
∠A = ∠B = ∠C
But ∠A + ∠B + ∠C = 180° (Sum of angles of a triangle)
∴ ∠A = ∠B = ∠C = \(\frac { { 180 }^{ \circ } }{ 3 }\)= 60°

Question 5.
Angles A, B, C of a triangle ABC are equal to each other. Prove that ∆ABC is equilateral.
Solution:
Given : In ∆ABC, ∠A = ∠B = ∠C
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q5.1
To prove : ∆ABC is an equilateral
Proof: In ∆ABC,
∴ ∠B = ∠C (Given)
∴ AC = AB …(i) (Sides opposite to equal angles)
Similarly, ∠C = ∠A
∴ BC =AB …(ii)
From (i) and (ii)
AB = BC = CA
Hence ∆ABC is an equilateral triangle

Question 6.
ABC is a right angled triangle in which ∠A = 90° and AB = AC. Find ∠B and ∠C.
Solution:
In ∆ABC, ∠A = 90°
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q6.1
AB =AC (Given)
∴ ∠C = ∠B (Angles opposite to equal sides)
But ∠B + ∠C = 90° (∵ ∠B = 90°)
∴ ∠B = ∠C = \(\frac { { 90 }^{ \circ } }{ 2 }\) = 45°
Hence ∠B = ∠C = 45°

Question 7.
PQR is a triangle in which PQ = PR and S is any point on the side PQ. Through S, a line is drawn parallel to QR and intersecting PR at T. Prove that PS = PT.
Solution:
Given : In ∆PQR, PQ = PR
S is a point on PQ and PT || QR
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q7.1
To prove : PS = PT
Proof : ∵ST || QR
∴ ∠S = ∠Q and ∠T = ∠R (Corresponding angles)
But ∠Q = ∠R (∵ PQ = PR)
∴ PS = PT (Sides opposite to equal angles)

Question 8.
In a ∆ABC, it is given that AB = AC and the bisectors of ∠B and ∠C intersect at O. If M is a point on BO produced, prove that ∠MOC = ∠ABC.
Solution:
Given : In ∆ABC, AB = AC the bisectors of ∠B and ∠C intersect at O. M is any point on BO produced.
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q8.1
To prove : ∠MOC = ∠ABC
Proof: In ∆ABC, AB = BC
∴ ∠C = ∠B
∵ OB and OC are the bisectors of ∠B and ∠C
∴ ∠1 =∠2 = \(\frac { 1 }{ 2 }\)∠B
Now in ∠OBC,
Ext. ∠MOC = Interior opposite angles ∠1 + ∠2
= ∠1 + ∠1 = 2∠1 = ∠B
Hence ∠MOC = ∠ABC

Question 9.
P is a point on the bisector of an angle ∠ABC. If the line through P parallel to AB meets BC at Q, prove that triangle BPQ is isosceles.
Solution:
Given : In ∆ABC, P is a point on the bisector of ∠B and from P, RPQ || AB is draw which meets BC in Q
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q9.1
To prove : ∆BPQ is an isosceles
Proof : ∵ BD is the bisectors of CB
∴ ∠1 = ∠2
∵ RPQ || AB
∴ ∠1 = ∠3 (Alternate angles)
But ∠1 == ∠2 (Proved)
∴ ∠2 = ∠3
∴ PQ = BQ (sides opposite to equal angles)
∴ ∆BPQ is an isosceles

Question 10.
ABC is a triangle in which ∠B = 2∠C, D is a point on BC such that AD bisects ∠BAC = 72°.
Solution:
Given: In ∆ABC,
∠B = 2∠C, AD is the bisector of ∠BAC AB = CD
To prove : ∠BAC = 72°
Construction : Draw bisector of ∠B which meets AD at O
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q10.1
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q10.2
RD Sharma Class 9 Solutions Chapter 12 Heron’s Formula Ex 12.3 Q10.3

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RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D

RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D

These Solutions are part of RS Aggarwal Solutions Class 10. Here we have given RS Aggarwal Solutions Class 10 Chapter 11 Arithmetic Progressions Ex 11D

Other Exercises

Very-Short and Short-Answer Questions
Question 1.
Solution:
(3y – 1), (3y + 5) and (5y+ 1) are in AP
(3y + 5) – (3y – 1) = (5y + 1) – (3y + 5)
⇒ 2 (3y + 5) = (5y + 1) + (3y – 1)
⇒ 6y + 10 = 8y
⇒ 8y – 6y = 10
⇒ 2y = 10
⇒ y = 5
y = 5

Question 2.
Solution:
k, (2k – 1) and (2k + 1) are the three successive terms of an AP.
(2k – 1) – k = (2k + 1) – (2k – 1)
⇒ 2 (2k – 1) = 2k + 1 + k
⇒ 4k – 2 = 3k + 1
⇒ 4k – 3k = 1 + 2
⇒ k = 3
k = 3

Question 3.
Solution:
18, a, (b – 3) are in AP
⇒ a – 18 = b – 3 – a
⇒ a + a – b = -3 + 18
⇒ 2a – b = 15

Question 4.
Solution:
a, 9, b, 25 are in AP.
9 – a = b – 9 = 25 – b
b – 9 = 25 – b
⇒ b + b = 22 + 9 = 34
⇒ 2b = 34
⇒ b= 17
a – b = a – 9
⇒ 9 + 9 = a + b
⇒ a + b = 18
⇒ a + 17 = 18
⇒ a = 18 – 17 = 1
a = 18, b= 17

Question 5.
Solution:
(2n – 1), (3n + 2) and (6n – 1) are in AP
(3n + 2) – (2n – 1) = (6n – 1) – (3n + 2)
⇒ (3n + 2) + (3n + 2) = 6n – 1 + 2n – 1
6n + 4 = 8n – 2
⇒ 8n – 6n = 4 + 2
⇒ 2n = 6
⇒ n = 3
and numbers are
2 x 3 – 1 = 5
3 x 3 + 2 = 11
6 x 3 – 1 = 17
i.e. (5, 11, 17) are required numbers.

Question 6.
Solution:
Three digit numbers are 100 to 990 and numbers which are divisible by 7 will be
105, 112, 119, 126, …, 994
Here, a = 105, d= 7, l = 994
Tn = (l) = a + (n – 1) d
⇒ 994 = 105 + (n – 1) x 7
⇒ 994 – 105 = (n – 1) 7
⇒ (n – 1) x 7 = 889
⇒ n – 1 = 127
⇒ n = 127 + 1 = 128
Required numbers are 128

Question 7.
Solution:
Three digit numbers are 100 to 999
and numbers which are divisible by 9 will be
108, 117, 126, 135, …, 999
Here, a = 108, d= 9, l = 999
T(l) = a + (n – 1) d
⇒ 999 = 108 + (n – 1) x 9
⇒ (n – 1) x 9 = 999 – 108 = 891
⇒ n – 1 = 99
⇒ n = 99 + 1 = 100

Question 8.
Solution:
Sum of first m terms of an AP = 2m² + 3m
Sm = 2m² + 3m
S1 = 2(1)² + 3 x 1 = 2 + 3 = 5
S2 = 2(2)² + 3 x 2 = 8 + 6=14
S3 = 2(3)² + 3 x 3 = 18 + 9 = 27
Now, T2 = S2 – S1 = 14 – 5 = 9
Second term = 9

Question 9.
Solution:
AP is a, 3a, 5a, …
Here, a = a, d = 2a
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 1

Question 10.
Solution:
AP 2, 7, 12, 17, …… 47
Here, a = 2, d = 7 – 2 = 5, l = 47
nth term from the end = l – (n – 1 )d
5th term from the end = 47 – (5 – 1) x 5 = 47 – 4 x 5 = 47 – 20 = 27

Question 11.
Solution:
AP is 2, 7, 12, 17, …
Here, a = 2, d = 7 – 2 = 5
an = a + (n – 1) d = 2 + (n – 1) x 5 = 2 + 5n – 5 = 5n – 3
Now, a30 = 2 + (30 – 1) x 5 = 2 + 29 x 5 = 2 + 145 = 147
and a20 = 2 + (20 – 1) x 5 = 2 + 19 x 5 = 2 + 95 = 97
a30 – a20 = 147 – 97 = 50

Question 12.
Solution:
Tn = 3n + 5
Tn-1 = 3 (n – 1) + 5 = 3n – 3 + 5 = 3n + 2
d = Tn – Tn-1 = (3n + 5) – (3n + 2) = 3n + 5 – 3n – 2 = 3
Common difference = 3

Question 13.
Solution:
T= 7 – 4n
Tn-1 = 7 – 4(n – 1) = 7 – 4n + 4 = 11 – 4n
d = Tn – Tn-1 = (7 – 4n) – (11 – 4n) = 7 – 4n – 11 + 4n = -4
d = -4

Question 14.
Solution:
AP is √8, √18, √32, …..
⇒ √(4 x 2) , √(9 x 2) , √(16 x 2), ………
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 2

Question 15.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 3

Question 16.
Solution:
AP is 21, 18, 15, …n
Here, a = 21, d = 18 – 21 = -3, l = 0
Tn (l) = a + (n – 1) d
0 = 21 + (n – 1) x (-3)
0 = 21 – 3n + 3
⇒ 24 – 3n = 0
⇒ 3n = 24
⇒ n = 8 .
0 is the 8th term.

Question 17.
Solution:
First n natural numbers are 1, 2, 3, 4, 5, …, n
Here, a = 1, d = 1
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 4
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 5

Question 18.
Solution:
First n even natural numbers are 2, 4, 6, 8, 10, … n
Here, a = 2, d = 4 – 2 = 2
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 6

Question 19.
Solution:
In an AP
First term (a) = p
and common difference (d) = q
T10 = a + (n – 1) d = p + (10 – 1) x q = (p + 9q)

Question 20.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 7

Question 21.
Solution:
2p + 1, 13, 5p – 3 are in AP, then
13 – (2p + 1) = (5p – 3) – 13
⇒ 13 – 2p – 1 = 5p – 3 – 13
⇒ 12 – 2p = 5p – 16
⇒ 5p + 2p = 12 + 16
⇒ 7p = 28
⇒ p = 4
P = 4

Question 22.
Solution:
(2p – 1), 7, 3p are in AP, then
⇒ 7 – (2p – 1) = 3p – 7
⇒ 7 – 2p + 1 = 3p – 7
⇒ 7 + 1 + 7 = 3p + 2p
⇒ 5p = 15
⇒ p = 3
P = 3

Question 23.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 8

Question 24.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 9
d = T2 – T1 = 14 – 8 = 6
Common difference = 6

Question 25.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 10

Question 26.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 11

Question 27.
Solution:
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 12
RS Aggarwal Class 10 Solutions Chapter 11 Arithmetic Progressions Ex 11D 13

Hope given RS Aggarwal Solutions Class 10 Chapter 11 Arithmetic Progressions Ex 11D are helpful to complete your math homework.

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RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2

RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2

These Solutions are part of RD Sharma Class 9 Solutions. Here we have given RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2

Other Exercises

Question 1.
Two opposite angles of a parallelogram are (3x- 2)° and (50 – x)°. Find the measure of each angle of the parallelogram.
Solution:
∵ Opposite angles of a parallelogram are equal
∴ 3x – 2 = 50 – x
⇒ 3x + x – 50 + 2
⇒ 4x = 52
⇒ x = \(\frac { 52 }{ 4 }\) = 13
∴ ∠A = 3x – 2 = 3 x 13 – 2 = 39° – 2 = 37°
∠C = 50° -x = 50° – 13 = 37°
But∠A + B = 180°
∴ 37° + ∠B = 180°
⇒ ∠B = 180° – 37° = 143°
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q1.1
and ∠D = ∠B (Opposite angles of a ||gm)
∴ ∠D = 143°
Hence angles and 37°, 143°, 37°, 143°

Question 2.
If an angle of a parallelogram is two-third of its adjacent angle, find the angles of the parallelogram.
Solution:
Let in ||gm ABCD,
∠A =x
Then ∠B = \(\frac { 2 }{ 3 }\) x
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q2.1
But, ∠A + ∠B = 180° (Sum of two adjacent angles of a ||gm)
⇒ x + \(\frac { 2 }{ 3 }\)x = 180°
⇒ \(\frac { 5 }{ 3 }\)x = 180°
⇒ x = 180° x \(\frac { 3 }{ 5 }\) = 108°
∴ ∠A = 108°
and ∠B = 108° x \(\frac { 2 }{ 3 }\) = 72°
But, ∠A = ∠C and ∠B = ∠D (Opposite angles of a ||gm)
∴ ∠C = 108°, ∠D = 72°
Hence angles are 108°, 72°, 108°, 72°

Question 3.
Find the measure of all the angles of a parallelogram, if one angle is 24° less than twice the smallest angle.
Solution:
Let smallest angle of a ||gm = x
Then second angle = 2x – 24°
But these are consecutive angles
∴ x + (2x- 24°) = 180°
⇒ x + 2x – 24° = 180°
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q3.1
⇒ 3x = 180° + 24° = 204°
⇒ x =\(\frac { { 204 }^{ \circ } }{ 3 }\)  = 68°
∴ Smallest angle = 68°
and second angle = 2x 68° – 24°
= 136°-24° = 112°
∵ The opposite angles of a ||gm are equal Other two angles will be 68° and 112°
∴ Hence angles are 68°, 112°, 68°, 112°

Question 4.
The perimeter of a parallelogram is 22 cm. If the longer side measures 6.5 cm what is the measure of the shorter side?
Solution:
In a ||gm ABC,
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q4.1
Perimeter = 22cm
and longest side = 6.5 cm
Let shorter side = x
∴ 2x (6.5 + x) = 22
⇒ 13 + 2x = 22
⇒ 2x = 22 – 13 = 9
⇒ x = \(\frac { 9 }{ 2 }\) = 4.5
∴ shorter side = 4.5cm

Question 5.
In a parallelogram ABCD, ∠D = 135°, determine the measure of ∠A and ∠B.
Solution:
In ||gm ABCD,
∠D = 135°
But, ∠A + ∠D = 180° (Sum of consecutive angles)
⇒∠A+ 135° = 180°
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q5.1
⇒ ∠A = 180° – 135° = 45°
∵ ∠B = ∠D (Opposite angles of a ||gm)
∴ ∠B = 135°

Question 6.
ABCD is a parallelogram in which ∠A = 70°. Compute ∠B, ∠C and ∠D.
Solution:
In ||gm ABCD,
∠A = 70°
But ∠A + ∠B = 180° (Sum of consecutive angles)
⇒ 70° + ∠B = 180°
⇒ ∠B = 180° – 70° = 110°
But ∠C = ∠A and ∠D = ∠B (Opposite angles of a ||gm)
∠C = 70° and ∠D = 110°
Hence ∠B = 110°, ∠C = 70° and ∠D = 110°
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q6.1

Question 7.
In the figure, ABCD is a parallelogram in which ∠DAB = 75° and ∠DBC = 60°. Compute ∠CDB and ∠ADB.
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q7.1
Solution:
In ||gm ABCD,
∠A + ∠B = 180°
(Sum of consecutive angles) But, ∠A = 75°
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q7.2
∴ ∠B = 180° – ∠A = 180° – 75° = 105°
∴ DBA = 105° -60° = 45°
But ∠CDB = ∠DBA (alternate angles)
= 45°
and ∠ADB = ∠DBC = 60°

Question 8.
Which of the following statements are true (T) and which are false (F)?
(i) In a parallelogram, the diagonals are equal.
(ii) In a parallelogram, the diagonals bisect each other.
(iii) In a parallelogram, the diagonals intersect each other at right angles.
(iv) In any quadrilateral, if a pair of opposite sides is equal, it is a parallelogram.
(v) If all the angles of a quadrilateral are equal, it is a parallelogram.
(vi) If three sides of a quadrilateral are equal, it is a parallelogram.
(vii) If three angles of a quadrilateral are equal, it is a parallelogram.
(viii)If all the sides of a quadrilateral are equal it is a parallelogram.
Solution:
(i) False, Diagonals of a parallelogram are not equal.
(ii) True.
(iii) False, Diagonals bisect each other at right angles is a rhombus or a square only.
(iv) False, In a quadrilateral, if opposite sides are equal and parallel, then it is a ||gm.
(v) False, If all angles are equal, then it is a square or a rectangle.
(vi) False, If opposite sides are equal and parallel then it is a ||gm
(vii) False, If opposite angles are equal, then it is a parallelogram.
(viii)False, If all the sides are equal then it is a square or a rhombus but not parallelogram.

Question 9.
In the figure, ABCD is a parallelogram in which ∠A = 60°. If the bisectors of ∠A and ∠B meet at P, prove that AD = DP, PC= BC and DC = 2AD.
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q9.1
Solution:
Given : In ||gm ABCD,
∠A = 60°
Bisector of ∠A and ∠B meet at P.
To prove :
(i) AD = DP
(ii) PC = BC
(iii) DC = 2AD
Construction : Join PD and PC
Proof : In ||gm ABCD,
∠A = 60°
But ∠A + ∠B = 180° (Sum of excutive angles)
⇒ 60° + ∠B = 180°
∴ ∠B = 1809 – 60° = 120°
∵ DC || AB
∠PAB = ∠DPA (alternate angles)
⇒ ∠PAD = ∠DPA (∵ ∠PAB = ∠PAD)
∴ AB = DP
(PA is its angle bisector, sides opposite to equal angles)
(ii) Similarly, we can prove that ∠PBC = ∠PCB (∵ ∠PAB = ∠BCA alternate angles)
∴ PC = BC
(iii) DC = DP + PC
= AD + BC [From (i) and (ii)]
= AD + AB = 2AB (∵BC = AD opposite sides of the ||gm)
Hence DC = 2AD

Question 10.
In the figure, ABCD is a parallelogram and E is the mid-point of side BC. If DE and AB when produced meet at F, prove thatAF = 2AB.
Solution:
Given : In ||gm ABCD,
E a mid point of BC
DE is joined and produced to meet AB produced at F
RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 Q10.1
To prove : AF = 2AB
Proof : In ∆CDE and ∆EBF
∠DEC = ∠BEF (vertically opposite angles)
CE = EB (E is mid point of BC)
∠DCE = ∠EBF (alternate angles)
∴ ∆CDE ≅ ∆EBF (SAS Axiom)
∴ DC = BF (c.p.c.t.)
But AB = DC (opposite sides of a ||gm)
∴ AB = BF
Now, AF = AB + BF = AB + AB = 2AB
Hence AF = 2AB

Hope given RD Sharma Class 9 Solutions Chapter 13 Linear Equations in Two Variables Ex 13.2 are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.