Question

The surface area of a sphere is found using the formula SA=4_r^2 where r is the radius. If the surface area of a sphere is 144_ square feet, what is the radius, in feet?

Answer 1

The answer is 6 feet.

The surface area (SA) is
SA = 4πr²
r - radius

It is given:
SA = 144π feet²
r = ?

Since SA = 4πr², then: 144π = 4πr²

π can be canceled out: 144 = 4r²
⇒ r² = 144 ÷ 4 = 36
⇒ r = √r² = √36 = 6