Question

PLEASE HELP IM SO CONFUSED
What is the surface area of a sphere with a radius of 9 units?

Answer 1

4 x pi x 9^2
the answer is D

Answer 2

The answer is D.
`324\pi(units)^(2)`

Explanation:

Given a sphere of radius R, the surface area of the sphere can be calculated using the following equation :

`A=4\pi(R)^(2)`

The area depends of the variable R ⇒

`A(R)=4\pi(R)^(2)`

To find the surface area, we replace
`R=9units` in the equation ⇒

`A(9units)=4\pi(9units)^(2)=4\pi81(units)^(2)=324\pi(units)^(2)`

The correct answer is D.
`324\pi(units)^(2)`