Question

The surface area of a sphere is found using the formula , where r is the radius. If the surface area of a sphere is 64 square feet, what is the radius, in feet? A. –4 B. 16 C. 4 D. –16

Answer 1

It should be C, I believe?

Explanation:

The surface area of a sphere can be found by the formula: A=4πr²

If the area is 64 square feet. -----> square feet means doubled

A=64² = 4096 feet

4096 =4πr² (divide 4π on both sides)

4096 ÷4π = 1024π

1024π = r² (square root r on both sides)

r = 56.718523229