If each edge of a cube is doubled, (i) how many times will its surface area increase? (ii) how many times will its volume increase?

(i) Let the edge of cube be l.
Since, Surface area of the cube (A)=6l²
When edge of cube is doubled, then
Surface area of the cube (A’)= 6(2l)² = 6x4l² = 4x6l²
A’ = 4 x A, Hence, the surface area will increase four times.
(ii) Volume of cube (V) = l³
When edge of cube is doubled, then volume of cube (V’)=(2l)³=8l³
V’ = 8 x V, Hence, the volume will increase 8 times.

Class 8 Maths Chapter 11 Exercise 11.4 Solution in Video

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