Question

What is the best approximation of the surface area of this right cone?

Answer 1

$\bf \textit{total surface area of a cone}\\\\ s=\pi r\sqrt{r^2+h^2}+\pi r^2\quad \begin{cases} r=radius\\ h=height\\ -----\\ r=12\\ h=9 \end{cases} \\\\\\ s=\pi (12)\sqrt{12^2+9^2}+\pi (12^2)\implies s=12\pi \sqrt{225}+144\pi \\\\\\ s=12\pi (15)+144\pi \implies s=180\pi +144\pi \implies s=324\pi$