[tex]\bf \textit{lateral surface area of a cylinder}\\\\
LA=2\pi rh~~
\begin{cases}
r=radius\\
h=height\\
-----\\
h=\stackrel{twice~r}{2r}\\
LA=16\pi
\end{cases}\implies 16\pi =2\pi r(2r)\implies 16\pi =4\pi r^2
\\\\\\
\cfrac{16\pi }{4\pi }=r^2\implies 4=r^2\implies \sqrt{4}=r\implies 2=r[/tex]
and since h = 2r, well, you know what that is.
