RD Sharma Class 8 Solutions Chapter 7 Factorization Ex 7.2

RD Sharma Class 8 Solutions Chapter 7 Factorization Ex 7.2

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.2

Other Exercises

Factorize the following :

Question 1.
3x-9
Solution:
3x – 9 = 3 (x – 3)        (HCF of 3, 9 = 3)

Question 2.
5x – 15x2
Solution:
5x- 15x2 = 5x (1 – 3x)
{HCF of 5, 15 = 5 and of x, x2 = x}

Question 3.
20a12b2 – 15a8b4
Solution:
20a12b2 – 15a8b4
{HCF of 20, 15 = 5, a12, a8 = a8, b2, b4 = b2}
= 5ab2(4a4 – 3b2)

Question 4.
72xy – 96x7y6
Solution:
72xy – 96x7y6
HCF of 72, 96 = 24 of x6x7 = x6, y7,y6 = y6
∴ 72x7y6 – 96x7y6 = 24x6y6 (3y – 4x)

Question 5.
20X3 – 40x2 + 80x
Solution:
20x3 – 40x2 + 80x
HCF of 20, 40,80 = 20
HCF of x3, x2, x = x
∴ 20x3 – 40x2 + 80x = 20x (x2 – 2x + 4)

Question 6.
2x3y2 – 4x2y3 + 8xy4
Solution:
2x3y2 – 4x2y3 + 8xy4
HCF of 2, 4, 8 = 2
HCF of x3, x2, x = 1
and HCF of y2, y3, y4 = y2
∴ 2x3y2 – 4x2y3 + 8xy4
= 2xy2 (x2 – 2xy + 4y2)

Question 7.
10m3n2 + 15m4n – 20m2n3
Solution:
10m3n2 + 15m4n – 20m2n3
HCF of 10, 15, 20 = 5
HCF of m3, m4, m2 = m2
HCF of n2, n, n3 = n
10m3n2 + 15m4n – 20m2n3
5m2n(2mn + 3m2– 4n2)

Question 8.
2a4b4 – 3a3b5 + 4a2b5
Solution:
2a4b4 – 3a3b5 + 4a2b5
HCF of 2, 3, 4= 1
HCF of a4, a3,
a2 = a2
HCF of b4, b5 b5 = b4
∴ 2a4b4 – 3a3b5 + 4a2b5 = a2b4
(2a2 – 3ab
+ 4b)

Question 9.
28a2 + 14a2b2 – 21a4
Solution:
28a2 + 14a2b2 – 21a4
HCF of 28, 14,21 =7
HCF of a2, a2, a4 = a2
HCF of 1, b2, 1 = 1
28a2 + 14a2b2-21a4 = 7a2
(4 + 2b2 – 3a2)

Question 10.
a4b – 3a2b2 – 6ab3
Solution:
a4b – 3a2b2 – 6ab3
HCF of 1,3,6 = 1
HCF of a4, a2, a = a
HCF of b, b2, b3 = b
∴ a4b – 3a2b2 – 6ab3 = ab (a3 – 3ab – 6b2)

Question 11.
2l2mn – 3lm2n + 4lmn2
Solution:
2l2mn – 3lm2n + 4lmn2
HCF 2, 3,4 = 1,
HCF of l2,l,l = l
HCF of m, m2, m = m
HCF of n, n, n2 = n
∴ 2lmn – 3lm2n + 4lmn2
= lmn (21 -3m + 4n)

Question 12.
x4y2 – x2y4 – x4y4
Solution:
x4y2 – x2y4 – x4y4
HCF of x4, x2, x4 = x2
HCF of y2, y4, y4 =y2
∴ x4y2 – x2y4 – x4y4 = x2y2 (x-y2 -x2y2)

Question 13.
9 x2y + 3 axy
Solution:
9 x2y + 3 axy
HCF of 9, 3 = 3
HCF of x2, x = x
HCF of y,y = y
HCF of 1,a = 1
∴ 9x2y + 3axy = 3xy (3x + a)

Question 14.
16m – 4m2
Solution:
16m – 4m2
HCF of 16, 4 = 4
HCF of m, m2 = m
∴ 16m – 4m2 = 4m (4 – m)

Question 15.
-4a2 + 4ab – 4ca
Solution:
-4a2 + 4ab – 4ca
HCF of 4, 4, 4 = 4
HCF of a2, a, a = a
∴ -4a2 + 4ab – 4ca = -4a (a – b + c)

Question 16.
x2yz + xy2z + xyz2
Solution:
x2yz + xy2z + xyz2
HCF of x2, x, x = x
HCF of y,y2,y=y
HCF of z, z,z2 = z
∴ x2yz + xy2z + xyz2 = xyz (x + y + z)

Question 17.
ax2y + bxy2 + cxyz
Solution:
ax2y + bxy2 + cxyz
HCF of x2, x, x = x,
HCF of y,y2,y = y
ax2y + bxy2 + cxyz = xy (ax + by + cz)

Hope given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.2 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.

RD Sharma Class 8 Solutions Chapter 7 Factorization Ex 7.1

RD Sharma Class 8 Solutions Chapter 7 Factorization Ex 7.1

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.1

Other Exercises

Find the greatest common factors (GCF / HCF) of the following polynomials : (1 – 14)

Question 1.
2x2 and 12x2
Solution:
2x2 and 12x2
HCF of 2 and 12 =2
HCF of x2,x2=x2
∴ HCF = 2x2

Question 2.
(6xy3 and 18x2y3
Solution:
6x3y and 18xy
HCF of 6, 18 = 6
HCF of x3 and x2 = x2
HCF of y and y3 -y
∴ HCF = 6x2y

Question 3.
7x, 21x2 and 14xy2
Solution:
7x, 21x2 and 14xy2
HCF of 7, 21 and 14 = 7
HCF of x, x2, x = x
∴ HCF = 7x

Question 4.
42x2yz and 63x3y2z3
Solution:
42x2yz and 63x3y2z3
HCF of 42 and 63 = 21
HCF of x2, x3 = x2
HCF of y,y2=y
HCF of z,z3 = z
∴ HCF = 21 x2yz

Question 5.
12ax2,6a2x3 and 2ax5
Solution:
12ax2, 6a2x3 and 2a3x5
HCF of 12, 6,2 = 2
HCF of a, a2, a3 = a
HCF of x2, x3, x5 = x2
∴ HCF = 2ax2

Question 6.
9x2, 15x2y3, 6xy2 and 21x2y2
Solution:
9x2, 15xV, 6xy2 and 21x2y2
HCF of 9, 15, 6,21 = 3
HCF of x2, x2, x, x2 = x
HCF of 1, y3, y2, y2 =2
∴ HCF = 3x

Question 7.
4a2b3 -12a3b, 18a4b3
Solution:
4a2b3, -12a3b, 18a4b3
HCF of 4, 12, 18 = 2
HCF of a2, a3, a4 = a2
HCF of b3,b, b3 = b
∴ HCF = 2a2b

Question 8.
6x2y2, 9xy3, 3x3y2
Solution:
6x2y2, 9xy3, 3x3y2
HCF of 6, 9, 3 = 3
HCF of x2, x, x3 = x
HCF of y2,y3,y2=y2
∴ HCF = 3xy2

Question 9.
a2b3, a3b2
Solution:
a2b3, a3b2
HCF of a2, a3 = a2
HCF of b3, b2 = b2
∴ HCF = a2b2

Question 10.
36a2b2c4, 54a5c2,90a4b2c2
Solution:
36a2b2c4, 54a5c2,90a4b2c2
HCF of 36, 54, 90 = 18
HCF of a2, a5, a4 = a2
HCF of b2, 1,b2= 1
HCF of c4,c2,c2 = c2
∴ HCF = 18a2 x 1 x c2 = 18a2c2

Question 11.
x3, – yx2
Solution:
x3, – yx2
HCF of x3, x2 = x2
HCF of 1, y= 1
∴ HCF = x2

Question 12.
15a3, -45a2, -150a
Solution:
15a3,-45a2,-150a
HCF of 15,45, 150 = 15
HCF of a3, a2, a = a
∴ HCF = 15a

Question 13.
2x3y2, 10x2y3, 14xy
Solution:
2x3y2, 10x2y3, 14xy
HCF of 2, 10, 14 = 2
HCF of x3, x2, x = x
HCF of y2,y3,y=y
∴ HCF = 2xy

Question 14.
14x3y5, 10x5y3, 2x2y2
Solution:
14x3y5, 10x5y3, 2x2y2
HCF of 14, 10, 2, = 2
HCF of x3, x5, x2 = x2
HCF of y5,y3,y2=y2
∴ HCF = 2xy

Find the greatest common factor of the terms in each of the following expressions:

Question 15.
5a4 + 10a3 – 15a2
Solution:
5a4 + 10a3– 15a2
HCF of 5, 10, 15 = 5
HCF of a4, a3, a2 = a2
∴ HCF = 5a2

Question 16.
2xyz + 3x2y + 4y2
Solution:
2xyz + 3x2y + 4y2
HCF of 2, 3,4 = 1
HCF of x, x2, 1 = 1
HCF of y,y,y2 =y
HCF of z, 1, 1 = 1
∴ HCF = y

Question 17.
3a2b2 + 4b2c2 + 12a2b2c2
Solution:
3a2b2 + 4b2c2 + 12a2b2c2
HCF of 3, 4, 12 = 1
HCF of a2, 1, a2 = 1
HCF of b2, b2, b2 = b2
HCF of 1, c2, c2 = 1
∴ HCF = b2

 

Hope given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.1 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 8 Solutions Chapter 20 Mensuration I Ex 20.3

RD Sharma Class 8 Solutions Chapter 20 Mensuration I (Area of a Trapezium and a Polygon) Ex 20.3

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3

Other Exercises

Question 1.
Find the area of the pentagon shown in the figure if AD = 10 cm, AG = 8 cm, AH = 6 cm, AF = 5 cm and BF = 5 cm, CG = 7 cm and EH = 3
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 1
Solution:
In the figure, here are three triangles and one trapezium.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 2
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 3
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 4

Question 2.
Find the area enclosed by each of the following figures as the sum of the areas of a rectangle and a trapezium:
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 5
Solution:
(i) In the figure ABCDEF,
Join CF, then, the figure consists one square and one trapezium ABCF is a square whose side = 18 cm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 6
Area of the square = 18 x 18 cm² = 324 cm²
Area of trapezium FCDE = \(\frac { 1 }{ 2 }\) (CF + ED) x 8 cm²
= \(\frac { 1 }{ 2 }\) (18 + 7) x 8
= \(\frac { 1 }{ 2 }\) x 25 x 8 cm²
= 100 cm²
Total area of fig. ABCDEF = 324 + 100 = 424 cm²
(ii) In the figure ABCDEF,
Join BE.
The figure consists of one rectangle BCDE and one trapezium ABEF
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 7
Area of rectangle BCDE = BC x CD = 20 x 15 = 300 cm²
Area of trapezium ABEF,
= \(\frac { 1 }{ 2 }\) (BE + AF) x height
= \(\frac { 1 }{ 2 }\) (15 + 6) x 8 cm²
= \(\frac { 1 }{ 2 }\) x 21 x 8 cm²
= 84 cm²
Area of the figure ABCDEF = 300 + 84 = 384 cm²
(iii) In the figure ABCDEFGH,
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 8
HC= AB = EF = 6 cm
AH = BC = 4 cm
DE = GF = 5 cm
Join HC.
In right ∆CDE,
ED² = CD² + CE²
⇒ (5)² = (4)² + (CE)²
⇒ 25 = 16 + (CE)²
⇒ (CE)² = 25 – 16 = 9 = (3)²
CE = 3 cm
The figure consist a rectangle and a trapezium
Area of rectangle ABCH = AB x BC = 6 x 4 = 24 cm²
Area of trapezium GDEF,
= \(\frac { 1 }{ 2 }\) (GD + EF) x CE 1
= \(\frac { 1 }{ 2 }\) (GH + HC + CD + EF) x CE
= \(\frac { 1 }{ 2 }\) (4 + 6 + 4 + 6) x 3 cm²
= \(\frac { 1 }{ 2 }\) x 20 x 3 cm²
= 30 cm²
Total area of the figure ABCDEFGH = 24 + 30 = 54 cm²

Question 3.
There is a pentagonal shaped park as shown in the figure. Jyoti and Kavita divided it in two different ways.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 9
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 10
Find the area of this park using both ways. Can you suggest some another way of finding its area ?
Solution:
In first case, the figure ABCDE is divided into 2 trapezium of equal area.
Now area of trapezium DFBC
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 11
Total area of the pentagon ABCDE = 2 x 168.75 = 337.5 m²
In second case, the figure ABCDE is divided into two parts, namely one square and other triangle.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 12
Total area of pentagon ABCDE = 225 + 112.5 = 337.5 m²

Question 4.
Find the area of the following polygon, if AL = 10 cm, AM = 20 cm, AN = 50 cm, AO = 60 cm and AD = 90 cm.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 13
Solution:
In the figure ABCDEF,
AD = 90 cm
BL = 30 cm
AO = 60 cm
CN = 40 cm
AN = 50 cm
EO = 60 cm
AM = 20 cm
FM = 20 cm
AL = 10 cm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 14
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 15
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 16
Area of ABCDEF = (150 + 800 + 900 + 200 + 1400 + 1600) cm² = 5050 cm²

Question 5.
Find the area of the following regular hexagon:
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 17
Solution:
In the regular hexagon MNOPQR There are two triangles and one rectangle.
Join MQ, MO and RP
NQ = 23 cm,
NA = BQ = \(\frac { 10 }{ 2 }\) = 5 cm
MR = OP = 13 cm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 18
In right ∆BDQ,
PQ² = BQ² + BP²
⇒ (13)² = (5)² + BP²
⇒ 169 = 25 + BP²
⇒ BP² = 169 – 25 = 144 = (12)²
BP = 12 cm
PR = MO = 2 x 12 = 24 cm
Now area of rectangle RPOM = RP x PO = 24 x 13 = 312 cm²
Area of ∆PRQ = \(\frac { 1 }{ 2 }\) x PR x BQ
= \(\frac { 1 }{ 2 }\) x 24 x 5 = 60 cm²
Similarly area ∆MON = 60 cm²
Area of the hexagon MNOPQR = 312 + 60 + 60 = 432 cm²

Hope given RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.3 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 8 Solutions Chapter 20 Mensuration I Ex 20.2

RD Sharma Class 8 Solutions Chapter 20 Mensuration I (Area of a Trapezium and a Polygon) Ex 20.2

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2

Other Exercises

Question 1.
Find the area, in square metres, of the trapezium whose bases and altitude are as under:
(i) bases = 12 dm and 20 dm, altitude =10 dm
(ii) bases = 28 cm and 3 dm, altitude = 25 cm
(iii) bases = 8 m and 60 dm, altitude = 40 dm
(iv) bases = 150 cm and 30 dm, altitude = 9 dm
Solution:
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 1
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 2
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 3

Question 2.
Find the area of trapezium with base 15 cm and height 8 cm. If the side parallel to the given base is 9 cm long.
Solution:
In the trapezium ABCD,
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 4
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 5

Question 3.
Find the area of a trapezium whose parallel sides are of length 16 dm and 22 dm and whose height is 12 dm.
Solution:
Length of parallel sides of a trapezium are 16 dm and 22 dm i.e.
b1 = 16 dm, b2 = 22 dm
and height (h) = 12 dm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 6

Question 4.
Find the height of a trapezium, the sum of lengths of whose bases (parallel sides) is 60 cm and whose area is 600 cm²
Solution:
Sum of parallel sides (b1 + b2) = 60 cm
Area of trapezium = 600 cm²
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 7

Question 5.
Find the altitude of a trapezium whose area is 65 cm² and whose bases are 13 cm and 26 cm.
Solution:
Area of a trapezium = 65 cm²
Bases are 13 cm and 26 cm
i.e. b1 = 13 cm, b2 = 26 cm.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 8

Question 6.
Find the sum of the lengths of the bases of trapezium whose area is 4.2 m² and whose height is 280 cm.
Solution:
Area of trapezium = 4.2 m²
Height (h) = 280 cm = 2.8 m.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 9

Question 7.
Find the area of a trapezium whose parallel sides of lengths 10 cm and 15 cm are at a distance of 6 cm from each other. Calculate the area as
(i) the sum of the areas of two triangles and one rectangle.
(ii) the difference of the area of a rectangle id the sum of the areas of two triangles.
Solution:
In trapezium ABCD, parallel sides or bases are 10 cm and 15 cm and height = 6 cm
Area of trapezium
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 10
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 11
Area of trapezium = 90 – 15 = 75 cm²
= area of rectangle – areas of two triangles.

Question 8.
The area of a trapezium is 960 cm². If the parallel sides are 34 cm and 46 cm, find the distance between them:
Solution:
Area of trapezium = 960 cm²
Parallel sides are 34 cm and 46 cm
b1 + b2 = 34 + 46 = 80 cm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 12
Distance between parallel sides = 24 cm

Question 9.
Find the area of the figure as the sum of the areas of two trapezium and a rectangle.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 13
Solution:
In the figure,
One rectangle is ABCD whose sides are 50 cm and 10 cm.
Two trapezium of equal size in which parallel sides are 30 cm and 10 cm and height
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 14

Question 10.
Top surface of a table is trapezium in shape. Find its area if its parallel sides are 1 m and 1.2 m and perpendicular distance between them is 0.8 m.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 15
Solution:
Top of a table is of trapezium in shape whose parallel sides are 1 m and 1.2 m and distance between them (h) = 0.8 m
Area of trapezium = \(\frac { 1 }{ 2 }\) (Sum of parallel sides) x height
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 16

Question 11.
The cross-section of a canal is a trapezium in shape. If the canal is 10 m wide at the top 6 m wide at the bottom, and the area of the cross-section is 72 m², determine its depth.
Solution:
Area of cross-section = 72 m²
Parallel sides of the trapezium = 10 m and 6 m
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 17

Question 12.
The area of a trapezium is 91 cm² and its height is 7 cm. If one of the parallel sides is longer than the other by 8 cm, find the two parallel sides.
Solution:
Area of trapezium = 91 cm²
Height (h) = 7 cm.
Sum of parallel sides
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 18
One parallel side = 9 cm
and second side = 9 + 8 = 17 cm
Hence parallel sides are 17 cm, 9 cm

Question 13.
The area of a trapezium is 384 cm². Its parallel sides are in the ratio 3 : 5 and the perpendicular distance between them is 12 cm. Find the length of each one of the parallel sides.
Solution:
Area of trapezium = 384 cm²
Perpendicular distance (h) = 12 cm
Sum of parallel sides
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 19
First parallel side = 8 x 3 = 24 cm
Second side = 8 x 5 = 40 cm

Question 14.
Mohan wants to buy a trapezium shaped field. Its side along the river is parallel and twice the side along the road. If the area of this field is 10500 m² and the perpendicular distance between the two parallel sides is 100 m, find the length of the side along the river.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 20
Solution:
Area of the trapezium shaped field = 10500 m²
and perpendicular distance between them (h) = 100 m.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 21

Question 15.
The area of trapezium is 1586 cm² and the distance between the parallel sides is 26 cm. If one of the parallel sides is 38 cm, find the other.
Solution:
Area of a trapezium = 1586 cm²
and distance between the parallel sides (h) = 26
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 22

Question 16.
The parallel sides of a trapezium are 25 cm and 13 cm ; Its nonparallel sides are equal each being 10 cm, find the area of the trapezium.
Solution:
Parallel sides of a trapezium ABCD are 25 cm and 13 cm
i.e. AB = 25 cm, CD = 13 cm
and each non-parallel side = 10 cm
i.e., AD = BC = 10 cm
From C, draw CE || DA and draw CL ⊥ AB
CE = DA = CB = 10 cm
and EB = AB – AE = AB – DC = 25 – 13 = 12 cm
Perpendicular CL bisects base EB of an isosceles ∆CED
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 23

Question 17.
Find the area of a trapezium whose parallel sides are 25 cm, 13 cm and other sides are 15 cm each.
Solution:
In trapezium ABCD, parallel sides are AB and DC.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 24
AB = 25 cm, CD = 13 cm
and other sides are 15 cm each i.e. AD = CB = 15 cm
From C, draw CE || DA and CL ⊥ AB
AE = DC = 13 cm
and EB = AB – AE = 25 – 13 = 12 cm
Perpendicular CL bisects the base EB of the isosceles triangle CEB
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 25

Question 18.
If the area of a trapezium is 28 cm² and one of its parallel sides is 6 cm, find the other parallel side if its altitude is 4 cm.
Solution:
Area of trapezium = 28 cm²
Altitude (h) = 4 cm.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 26
One of the parallel side = 6 cm
Second parallel side = 14 – 6 = 8 cm

Question 19.
In the figure, a parallelogram is drawn in a trapezium the area of the parallelogram is 80 cm², find the area of the trapezium.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 27
Solution:
Area of parallelogram (AECD) = 80 cm²
Side AE (b) = 10 cm
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 28

Question 20.
Find the area of the field shown in the figure by dividing it into a square rectangle and a trapezium.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 29
Solution:
Produce EF to H to meet AB at H and draw DK || EH
HF = 4 cm, KD = HE = 4 + 4 = 8 cm
HK = ED = 4 cm,
KB = 12 – (8) = 4 cm
Now, area of square AGFH = 4 x 4 = 16 cm²
area of rectangle KDEH = l x b = 8 x 4 = 32 cm²
and area of trapezium BCDK.
RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 30
Total area of the figure = 16 + 32 + 22 = 70 cm²

Hope given RD Sharma Class 8 Solutions Chapter 20 Mensuration I Ex 20.2 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.

RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7

RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7

Other Exercises

Question 1.
Find the following products :
RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7 1
Solution:
RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7 2
RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7 3
RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7 4

Question 2.
Evaluate the following :
(i) 102 x 106
(ii) 109 x 107
(iii) 35 x 37
(iv) 53 x 55
(v) 103 x 96
(vi) 34 x 36
(vii) 994 x 1006
Solution:
(i) 102 x 106 = (100 + 2) (100 + 6)
= (100)2 + (2 + 6) x 100 + 2 x 6
= 10000 + 800 + 12 = 10812

(ii) 109 x 107 = (100 + 9) (100 + 7)
= (100)2 + (9 + 7) x 100 + 9 x 7
=10000 + 1600 + 63 = 11663

(iii) 35 x 37 = (30 + 5) (30 + 7)
= (30)2 + (5 + 7) x 30 + 5 x 7
= 900 + 12 x 30 + 35
= 900 + 360 + 35 = 1295

(iv) 53 x 55 = (50 + 3) (50 + 5)
= (50)2 + (3 + 5) x 50 + 3 x 5
= 2500 + 8 x 50 + 15
= 2500 + 400+ 15 = 2915

(v)103 x 96 = (100 + 3) (100-4)
= (100)2 + (3 – 4) x 100 + 3 x (-4)
= 10000+ (-1) x 100-12
= 10000 – 100 – 12 = 10000 – 112 = 9888

(vi) 34 x 36 = (30 + 4) (30 + 6)
= (30)2 + (4 + 6) x 30 + 4 x 6
= 900 + 10 x 30 + 24
= 900 + 300 + 24 = 1224

(vii) 994 x 1006 = (1000 – 6) (1000 + 6)
= (1000)2 + (-6 + 6) x 1000 + (-6) x 6
= 1000000 + 0-36
= 1000000-36 = 999964

Hope given RD Sharma Class 8 Solutions Chapter 6 Algebraic Expressions and Identities Ex 6.7 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.