The vertices of the regular -gon are marked on a circle. Two players play the following game. They, in turn, delete exactly one of the vertices. The player wins if after his move all triangles with the vertices in the remained points are obtuse.
Who of the player wins if both of them play to win?
Belarusian Mathematical Olympiad
Solution
4. See the 38th All-Russian Mathematical Olympiad, Final Round, Problem 11.7.
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