[tex]\bf \textit{surface area of a sphere}\\\\
A=4\pi r^2\qquad
\begin{cases}
r=radius\\
-----\\
A=36\pi
\end{cases}\implies 36\pi =4\pi r^2
\\\\\\
\cfrac{36\pi }{4\pi }=r^2\implies 9=r^2\implies \sqrt{9}=r\implies \boxed{3=r}\\\\
-------------------------------\\\\
\textit{volume of a sphere}\\\\
V=\cfrac{4}{3}\pi r^3\qquad \qquad \implies V=\cfrac{4}{3}\cdot \pi \cdot 3^3\implies V=4\pi 9\implies \boxed{V=36\pi }[/tex]
