SOLUTION: A circle is inscribed in a square. What is the probability that a penny, if thrown, will fall in the shaded region?

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Question 1143604: A circle is inscribed in a square. What is the probability that a penny, if thrown, will fall in the shaded region?
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200) (Show Source):
You can put this solution on YOUR website!

What shaded region...?

Let r be the radius of the circle; then the side of the square is the diameter of the circle, which is 2r.

area of square:
area of circle:

P(penny lands inside the circle) =

P(penny lands inside the square but outside the circle) =

Use that to find the probability that the penny lies in your shaded region.

Answer by ikleyn(52786) (Show Source):
You can put this solution on YOUR website!
.

Penny can be partly in the shaded and partly in the unshaded region.

In this sense, the problem formulation is not perfect.