The volume of the inscribed cone of a ball can be expressed as:

V=[π(Rsinα)(Rsinα)(Rcosα+R)]/3

Where the angle α is the included angle between the radius of the ball connected to the bottom surface of the cone and a straight line perpendicular to the bottom surface of the cone.

This shows that,

v =πRRR[(sinα)(sinα)(cosα+ 1)]/3

=(32πRRR)/8 1

It shows that RRR means the cube of R.

If you feel uncomfortable, you can also write v = 32 π r 3/8 1.

(r 3 = RRR = r cube)