Answer: 10.6 ft
Step-by-step explanation:
[tex]V = \dfrac{1}{3}\pi r^2h\\\\144 =\dfrac{1}{3}\pi r^2(12)\\\\144 =4\pi r^2\\\\\dfrac{144}{4\pi}=r^2\\\\\\\sqrt{\dfrac{36}{\pi}}=\sqrt{r^2}\\\\\\\dfrac{6}{\sqrt{\pi}}=r\\\\\\10.6=r[/tex]
