What is the volume of a circle with a 60 foot diameter

Circles don't have volume, but they do have area.

The area of any circle is ...

(pi) x (the circle's radius) ².

The circle's radius is 1/2 of its diameter.

So for the circle in the question,

Radius = 30-ft

Area = (pi) x (900 square ft) = 2,827 square feet (rounded)