V = [tex] \pi \pi [/tex][tex] r^{2}[/tex]h
1. Find the radius.
8/2 = 4
2. Square the radius.
[tex] 4^{2} [/tex] = 16
3. Multiply that by pi.
3.14 * 16 = 50.24
4. Multiply that by the height.
50.24 * 20 = 1004.8
5. Now find 60% of that.
1004.8 * 0.6 = 602.88
V = 602.88 [tex] m^{3}[/tex]
Honestly, it's been a while since I've done this, but I believe this is the answer.