2 answers
(click or scroll down)
V = (4/3) pi r^3
= 4.189 r^3
so
r = V^(1/3)/(4.189)^(1/3)
r = .620 V^(1/3) I thought they were off a bit.
Ok, using r = .6 V^(1/3)
r = .6 *729^(1/3)
r = .6 * 9
r = 5.40 meters