[tex]\bf \textit{surface area of a sphere}\\\\
S=4\pi r^2\qquad
\begin{cases}
r=radius\\
-----\\
S=16\pi
\end{cases}\implies 16\pi =4\pi r^2\implies \sqrt{\cfrac{16\pi }{4\pi }}=\boxed{r}
\\\\\\
\textit{volume of a sphere}\\\\
V=\cfrac{4}{3}\pi r^3\implies V=\cfrac{4}{3}\pi \cdot \boxed{\sqrt{\cfrac{16\pi }{4\pi }}}[/tex]
simplify away
