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MathNet 2012 Question 55

Math Olympiad Vault · MathNet 2012

Question 55

A mouse lives in a circular cage with completely reflective walls. At the edge of this cage, a small flashlight with vertex on the circle whose beam forms an angle of $15^{\circ}$ is centered at an angle of $37.5^{\circ}$ away from the center. The mouse will die in the dark. What fraction of the total area of the cage can keep the mouse alive?
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