Question

A sphere and a hemisphere have the same surface area. the ratio of their volumes is :

Answer 1

surface area of sphere =

$4\pi(r)^{2}$
so, surface area of hemisphere =
$2\pi(r) ^{2}$
bcoz it is half of hemisphere.
A/q both r equal therefore.
$4\pi(r)^{2} \div 2\pi(r) ^{2}$
= 2:1