The formula for volume of a cylinder is V=π r^2 h. So plug in, 320π=<span>π r^2 20 solve (sadmep (opposite of pemdas)) divide pi out 320=r^2 20 divide 20 out 16=r^2 square root of 16 is 4, so the radius is 4. Since the 2r=d, the diameter is 8. P.s. lol it thought I was copying an answer from online...
