Surface area

Question

A sphere has a surface area of 80 square feet. Which choice is the closest to its radius? Use 3.14 to approximate pi.

Answer 1

S = 4·pi·r²

• S = surface area of sphere = 80 sq. ft.
• pi = 3.14
• r = radius

 

S = 4·pi·r²

80 = 4·(3.14)·r²

Solve for r