Question

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

144π ft2


396π ft2


252π ft2


540π ft2

Answer 1

`396\pi \: {ft}^(2)`

Explanation:

Given:

A cone

l = 21 ft

r = 12 ft

Find: A (surface) - ?

`a(surface) = \pi {r}^(2) + \pi * r * l`

`a(surface) = \pi * {12}^(2) + \pi * 12 * 21 = 144\pi + 252\pi = 396\pi \: {ft}^(2)`