Answer
$\frac{\sqrt[3] (r^{2})}{2}$
Work Step by Step
The quotient rule for radicals tells us that $\sqrt[n] \frac{a}{b}=\frac{\sqrt[n] a}{\sqrt[n] b}$ (if $\sqrt[n] a$ and $\sqrt[n] b$ are real numbers and $n$ is a natural number). That is, the nth root of a quotient is the quotient of the nth roots.
Therefore, $\sqrt[3] \frac{r^{2}}{8}=\frac{\sqrt[3] (r^{2})}{\sqrt[3] 8}=\frac{\sqrt[3] (r^{2})}{2}$.
$\sqrt[3] 8=2$, because $2^{3}=8$
