Volume of a barrel.

[ggauny@live.fr]

Hi,
My question is how exactely find the exact capacity of a barrel and why it is not a unique answer, and why so many equations ?
Me I dont' know what is parabola or eliptic curve, so for my excercise to do for
I encounter problems of course.
Dieter was speaking of Kepler, so I had remember in my "very" old book of geometrie, when I was in school before go to work there is a solution without complicated formulas.
I will do my excercise like in this time.