Question 791203
Not really possible unless you accept an approximation.  Pi is irrational.  You could give the final value for computed V,  IN TERMS of pi and, depending on what you have for r, you could make (4/3)*r^3 as rational, but then you still include pi.  If r is rational, no trouble.  If r is irrational, then V will be reported as {{{SomethingIrrational*pi}}}.


This can be more specific for you if you tell what you have for r.