Telanagana SCERT Solution Class VIII (8) Math Chapter 14 Surface Areas And Volume Exercise 14.2
(1)
Sl No. | Length | Breadth | Height | Volume |
(i) | 8.2 m | 5.3 m | 2.6 m | 8.2 x 5.3 x 2.6 = 99 m3 |
(ii) | 5.0 m | 4.0 m | 3.5 m | 5 x 4 x 3.5 = 70 m3 |
(iii) | 4.5 m | 2.0 m | 2.5 m | 4.5 x 2.0 x 2.5 = 22.5 |
(2)
Length | Breadth | Height | Volume | |
(i) | 3 m 20 cm | 2 m 90 cm | 1 m 50 cm | 3.2 x 2.9 x 1.5 = 13.92 m2 |
(ii) | 2 m 50 cm | 1 m 60 cm | 1 m 30 cm | 2.5 x 1.6 x 1.3 = 5.2 m2 |
(iii) | 7 m 30 cm | 3 m 60 cm | 1 m 40 cm | 7.3 x 3.6 x 1.4 = 36.79 m2 |
(3)
Let, the length of the cube x.
So, volume of cube = x3
If length reduced to half then length become x/2
Then volume = (x/3)3 = x3 / 8
The volume reduced by 1/8 unit3
(4) (i) Sides = 6.4 cm
Then volume = (6.4)3 = 262.14 cm3
(ii) Sides = 1.2 m2
Then volume = (1.3)3 = 2.19 m3
(iii) Sides = 1.6 m
So volume = (1.6)3 = 4.09 m3
(5) length of the wall = 8 m = 800 cm
Height of the wall = 6 m = 600 cm
Breadth of the wall = 22.5 cm
Volume of the wall = 800 x 600 x 22.5
= 10800000 cm3
Then, length of the brick = 25 cm
Height of the brick = 6 cm
Breadth of the brick = 11.25 cm
Volume of the brick = 25 x 6 x 11.25 = 1687.5 cm3
∴ Number of bricks need = 10800000/1687.5
= 6400 pieces.