Oh yes... Wonderful Proportions. There are ways to do proportions but this is how I learned how to do them :
PART %
=
WHOLE 100 That is the formula. I'm not sure of an example but I hope it helps
Using the formula:
V= 1/6 πd^3
V ≈ 1838.78
X 65%
———— = ———-
90 100
1) multiply across
90 • 65 = 5,850
2) divide what’s left over.
5,850 / 100 = 58.5