What is the surface area of a sphere with a circumference of 50 ft? Round the answer to the nearest tenth.

The surface area of a sphere is:

A=4πr^2

And the circumference of a sphere (or circle) is:

C=2πr

Solving for r, r=C / (2π), and using that for r in the area equation gives you:

A=4π (C / (2π) ^2

A=4π (C^2 / (4π^2))

A = (4πC^2) / (4π^2)

A = (C^2) / π, since we are told that C=50 ft

A=2500/π ft^2

A≈795.8 ft^2 (to nearest tenth)