Question

What is the surface area of the cone? Express your answer in terms of π.b

Answer 1

Given:

Radius of the cone = 5 ft

Slant height of the cone = 21 ft

To find:

The surface area of the cone

Solution:

Surface area of cone formula:

$SA=\pi r^{2}+\pi r l$

where r is the radius and l is the slant height.

$SA=\pi \times 5^{2}+\pi \times 5 \times 21$

$SA=\pi \times 25+\pi \times 105$

$SA=25 \pi+ 105 \pi$

$SA=130 \pi$

The surface area of the cone is 130π square feet.