What is the Formula for the volume of a spherical solid?

A sphere is a revolution of a semi circle about the x axis.

The formula for this type of volume is the integral of pi*f2(x)*dx. so if a circle can be described by the formula x2+y2=r2 where r is the radius. so then

f(x)=sqrt(r2-x2) so then we square f2(x).... =r2-x2 then we multiply by pi so we have pi*r2 - pi*x2 next we integrate this so have pi*r2x evaluted at r and -r and we also have -(1/3)*pi*x3 evaluted at r and -r once we evalute this we have (4/3)*pi*r3