I asked this before and did not get a response so I am trying again. (Note, I didn't know how to type the symbol for pi)

What is the derivative of:

2pi^2r^4

would it simply be 8pi^2r^3?

I was thinking the 2pi^2 is simply the equivalent of a constant in front of the r^4 and so you would just use the power rule.

correct, your thinking is right on