hey user!
your answer is here..
given the diameter of the sphere is 12 ft.
therefore radius of the sphere = 12/2 = 6 ft
[tex]volume \: of \: the \: sphere = \frac{4}{3} \pi {r}^{3} \\ = \frac{4}{3} \pi( {6}^{3} ) \\ \\ = \frac{4}{3} \pi(216) \\ \\ = 288\pi {ft}^{3} \\ \\ cheers...[/tex]