Question

the radius of a spherical bollon increase from 7cm to 14cm as ais is being pumbed into it. find the ratio of surface area of the ballon in the two cases​

Answer 1

Surface area 1
r=7cm
$= 4\pi {r}^{2}$
Surface area 2
R=14cm
=4πR^2

Ratio
=(4πr^2)/(4πR^2)
=(7×7)/(14×14)
=1/4