Remember
this problem? The one where you had to find the area between two circles by only knowing the length of the tangent "chord" (the red line)?
That problem is solved using some (moderately) tricky geometry. But if you know that the problem is solvable, it's actually pretty easy to solve by simply using the formula for the area of the circle and a bit of logic.
Can you do it?
Just wondering why EVERYONE here assumes the chord is 10 inches when explaining their solutions? Is there something that leads them to that number??? I smell a rat...probably that other problem that's similar states a chord length of 10 and people are just transposing??
Whatever...