I need to find the circle area of a cylinder with a depth of 4ft and can't exceed a volume of 4500ft³

So we have

4500 = pi * r^2 * 4     divide both sides by 4 pi

4500/[4 pi] = r^2  = (1125/pi)   take the sq root of each side

√(1125/pi) = r = about 18.923 ft   (at most)

So the circular area is just pi * r^2  = pi *(18.923)^2 = about 1124.94 sq ft  (at most)