Question

Find the surface area of the cone in terms of pie.

A 90 (pie) cm^2

B 180 (pie) cm^2

C 144 (pie) cm^2

D 108 (pie) cm ^2

Answer 1

Check the picture below.

`\bf \textit{surface area of a cone}\\\\ SA=\pi r√(r^2+h^2)+\pi r^2~~ \begin{cases} ~\hfill r&=radius\\ ~\hfill h&=height\\ √(r^2+h^2)&=slant~height\\[-0.5em] \hrulefill&\hrulefill\\ ~\hfill r&=6\\ √(r^2+h^2)&=18 \end{cases} \\\\\\ SA=\pi (6)(18)+\pi (6)^2\implies SA=108\pi +36\pi \implies SA=144\pi`