Answer
$r = \sqrt {\frac{3V}{\pi h}}$
Work Step by Step
$Solve$ $the$ $equation$ $for$ $the$ $indicated$ $variable:$
$V = \frac{1}{3}\pi r^2h;$ $for$ $r$
Solve for $r$
Multiply both sides by 3
$3\times V = 3(\frac{1}{3}\pi r^2h)$
$3V = \pi r^2h$
Divide Both sides by $\pi h$
$\frac{3V}{\pi h} = \frac{\pi r^2h}{\pi h}$
$\frac{3V}{\pi h} = r^2$
Square root both sides
$\sqrt {r^2} = \sqrt {\frac{3V}{\pi h}}$
$r = \sqrt {\frac{3V}{\pi h}}$
