integrate along vertiakal...seerees av thin serkels (disk).
eech disk hav area=pi*r*r. thik =deltaz
disk volume=area*deltaz
integrate dz from 0 tu hite.
But, first: r=R0*(1-z/hite)
so integrate pi z^2 dz from 0 tu hite
anser=(1/3)pi*r^3, evaluated at r=0 & at r=hite
=(1/3)(area av base)*hite