The volume of a sphere is a function of its radius, v equals four thirds pi r cubed. evaluate the function for the volume of a volleyball with radius 10.7 cm the volume is? ... cm cubed

V = (4/3) * pi * r^3

radius equals diameter divided by 2:

r = d/2

replace r with (d/2) to get:

v = (4/3) * pi * (d/2) ^3

(d/2) ^3 is the same as (1/2) ^3 * d^3 so your equation becomes:

v = (4/3) * pi * (1/2) ^3 * d^3 which becomes:

v = (4/3) * pi * (1/8) * d^3