[tex]\bf \textit{surface area of a sphere}\\\\ SA=4\pi r^2~~ \begin{cases} r=radius\\ \cline{1-1} r=8 \end{cases}\implies SA=4\pi (8)^2\implies SA=256\pi \\\\\\ \stackrel{\textit{half of that for a \underline{hemi}sphere}}{\cfrac{256\pi }{2}\implies 128\pi \implies }\stackrel{\textit{rounded up}}{402.1}[/tex]
