Remember that the volume of a cone is [tex]1/3 \pi r^2h[/tex]
Thus;
1. 2^2 = 4
4pi(7) = 28pi
28/3 = [tex]9 \frac{1}{3} [/tex]
ANS = [tex]9 \frac{1}{3} \pi [/tex] or ~29.32
2. d = 18, r = 9
9 ^ 2 = 81
81pi (18) = 1458pi
1458 / 3 = 486
ANS = [tex]486 \pi [/tex] or ~1526.81