Question

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

A. 792
B. 566
C. 4070
D. 1020

Answer 1

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