Question

Select the closest answer. *

20 points
1. Find the surface area of a sphere with a radius of 4.2 centimeters.
A. 235.6 cm?
C. 121.4 cm
B. 310.3 cm
D. 221.7 cm
A
B
С
OD
Select the closest answer.

Answer 1

D. 221.7 cm

Explanation:

Surface area of a sphere is:
`SA=4\pi r^2`

'r' - radius

We are given the radius of 4.2 centimetres.

`SA=4\pi 4.2^2\\4 * \pi * 4.2^2\\\rightarrow 4.2^2 =17.64\\\text {Using 3.14 for pi: }\\4 * 3.14 *17.64\\12.56*17.64\\\boxed {221.5584}`

221.5584 ≈ 221.6

The closest answer is Option D, therefore it should be the correct answer.