Given #A=2(pi)r^2 + 2(pi)rh#, how do you solve for r?
This cannot be done.
My thinking here says that it cannot be done, because there are two different powers of r involved. If you try to factor out the r as a common factor, there will still be an r in the first term.
Use the quadratic formula to get
Although at first it seems like we can't solve, for
Note that if subtract
If we take out the
We know that
Making the substitutions
Certainly not the cleanest expression, but it will do.