Question

The surface area of a cone is 16 pi inches squared. The radius is 3 inches. What is the slant height?

Answer 1

hmmm

Answer 2

am I wrong by using instead

\(\bf \textit{area of a cone } = \pi r \sqrt{r^2+h^2} + \pi r^2\\
\color{blue}{h = \textit{height of the cone}\\
\sqrt{r^2+h^2} = \textit{slant height}}\\
\textit{area of a cone } = \pi r (\textit{slant height})+ \pi r^2 \implies \pi r ((\textit{slant height})+r)\\
16 \pi = \pi 3 ((\textit{slant height})+3)\)