Math Help - Volume, center of a mass and moment of inertia of a reqular square pyramid

Hi,

In this problem I have a regular square pyramid (base length a , height b) and it's spun about its axis symmetry of z.

How do I find it's Volume?

And center of mass?

How about the moment of intertia of the pyramid?

Thank you for your help as I've been stuck with this for while.








I know it needs to be divided into sub-bodies and then use integral.