Question

# If the surface area of a hemisphere is ‘S’, then express ‘r’ in terms of ‘S’.

Hint: Curved Surface Area (CSA) of hemisphere$S = 2\pi {r^2}$
Curved Surface Area (CSA) of a Hemisphere is given by the formula$S = 2\pi {r^2}$ …(1)
$\begin{gathered} S = 2\pi {r^2} \\ {r^2} = \dfrac{S}{{2\pi }} \\ r = \sqrt {\dfrac{S}{{2\pi }}} \\ \end{gathered}$
The required formula is $r = \sqrt {\dfrac{S}{{2\pi }}}$