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MathNet 2019-part-08 — 179 problems (EN–VI) Question 144

Math Olympiad Vault · MathNet 2019-part-08 — 179 problems (EN–VI)

Question 144

Will stands at a point $P$ on the edge of a circular room with perfectly reflective walls. He shines two laser pointers into the room, forming angles of $n^{\circ}$ and $(n+1)^{\circ}$ with the tangent at $P$, where $n$ is a positive integer less than $90$. The lasers reflect off of the walls, illuminating the points they hit on the walls, until they reach $P$ again. ($P$ is also illuminated at the end.) What is the minimum possible number of illuminated points on the walls of the room?

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