Question

a cone has a height of 4, diameter of 6 , and a slant length of 5. what is the surface area of the cone?

Answer 1

24π or 75.4

Explanation:

The equation for the surface area is SA=πr²+πrl

Since the diameter is 6, then the radius will be 3

Plug the values in:

π3²+π×3×5

9π+15π

24π =75.39822

Answer 2

since the cone's diameter is 6, its radius must be 3 then.

`\bf \textit{total surface area of a cone}\\\\ SA=\pi rs+\pi r^2~~ \begin{cases} r=&radius\\ s=&slant~height\\ \cline{1-2} r=&3\\ s=&5 \end{cases}\implies SA=\pi (3)(5)+\pi (3)^2 \\\\\\ SA=15\pi +9\pi \implies SA=24\pi \implies SA\approx 75.398`