# Math Help - Finding the area of a circle inscribed another circle

1. ## Finding the area of a circle inscribed another circle

So here's the question and the highlighted answer.

Here's what I did to solve it, but I don't come up with the correct answer. What am I doing wrong here?

2. Originally Posted by thumpin_termis
So here's the question and the highlighted answer.

Here's what I did to solve it, but I don't come up with the correct answer. What am I doing wrong here?
You misread the question, the medalian is the colored glass + the frame, so r is the outer radius and r - s is the inner radius. thus your equation should be:

$A = \pi r^2 - \pi (r - s)^2$

3. Ah ha. I see. Now I get the correct answer. Thank you!