Question

If side of a cube is doubled then,

(i) How many times its surface area will increase?

(ii) How many times its volume will increase?

Answer 1

(i) Let a cm. be the side of cube. Then,

Surface Area S₁ = 6a² cm²

New side = 2a cm.

.’. New Surface Area S₂ = 6 (2a)²

= 24a² cm²

We get,

S₂ = 4 S₁

Hence, the surface area of new cube will increase 4 times.

(ii) Volume V₁ = a³ cm³

Hence, the volume will increase 8 times.