Check out some similar questions!

guria1 · Aug 20, 2009, 10:06 AM

I don't get how to solve this math problem:
I have to solve for r>0
A=2pie*(r squared) + s=2pie*r*h

when I take everything over to the other side, I have r + r squared left on one side. Now I don't get how to combine r and r squared. Please help!!

Unknown008 · Aug 20, 2009, 10:15 AM

Firstly, $\pi$ is pi, not pie as in apple pie.

I think you're speaking of the formula for the total surface area of a cylinder, right? Then, don't put is the way you did, since it causes confusion. Also, your question is also confusing in the way that you want to solve for r>0. If r>0, then A>0. But if you want to make r the subject of formula, then that's something else.

$A = 2\pi r^2 + S$

$S = 2 \pi rh$

$A= 2\pi r^2 + 2\pi rh = 2\pi (r^2 + rh)$

$\frac{A}{2 \pi}= (r^2 + rh)$

You cannot go any further if you don't have any more information. If it was given for example, the height h = 2r, then, you can go on.