Question

The radius of a spherical balloon is inflated from $1.5cm$ to $2.5cm$ by pumping more air in it. Find the ratio of surface area of resulting balloon to the original balloon.

Answer 1

Surface area of sphere=4$\pi (r{)}^2$

$S_1=4\pi (1.5{)}^2$

$S_2=4\pi (2.5{)}^2$

Ratio of $S_{1}and{S}_2$

$\frac{S_1}{S_2}=\frac{1.5\times 1.5}{2.5\times 2.5}$

$\frac{S_1}{S_2}=\frac{3\times 3}{5\times 5}$

$\frac{S_1}{S_2}=\frac{9}{25}$