how do i find an area of a shaded region inside a large semi-circle with a smaller semi circle inside if i'm only given the diameter of the large semi circle?

Question

anonymous · Answer

it looks like this...

thread252 · Answer

first you need to find the radius of the circle, then find the area of the large circle. divide that by 2 to get the area of the large half circle. 
to find the area of the small circle you need to have the radius of the small circle, which you don't seem to have one. so all i can tell you is that you find the area of the small circle the same way you find the area of the big circle