4/3pi *r3 = 972pi
Divide both side by pi
4/3 *r3 = 972
r3 = 972* 3/4
r3 = 729
r = the square root of 729 to the third power (I don't know if I'm expressing this correctly but answer is 9, hope you get that)
r = 9 that's your answer.
Hope it's correct, appreciate if you could let me know