hi how r u

$$r*U = r*(2*\pi *r)=2*\pi*r^2=2*(\pi*r^2)=2*A\quad \quad U=2\pi r$$

$$\boxed{rU=2A}$$

Well, I just woke up and I have a hands-on test in Biology in a little over an hour, so right now I'm kinda out of it.

not the greatest... i have to take a test tomorrow (Friday) in math and english.