V=4/3×π×r³
The volume is given, so we substitute it to the formula to get the equation and solve it for r.
[tex] \displaystyle 972 \pi = \frac{4}{3} \pi r^3 \Rightarrow 972 \pi= \frac{4 \pi r^3}{3} [/tex]
[tex] \displaystyle 4 \pi r^3 = 972 \pi \cdot 3 \Rightarrow 4 \pi r^3 = 2916 \pi [/tex]
[tex] \displaystyle r^3 = \frac{2916 \pi}{4 \pi} \Rightarrow r^3=729 \Rightarrow r=\sqrt[3]{729}=9 [/tex]
r = 9 in is your answer
