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At least one of the 7 arcs created is at most 1/24

Source: Pan African Olympiad 2010

October 1, 2011
pigeonhole principlecombinatorics proposedcombinatorics

Problem Statement

Seven distinct points are marked on a circle of circumference cc. Three of the points form an equilateral triangle and the other four form a square. Prove that at least one of the seven arcs into which the seven points divide the circle has length less than or equal c24\frac{c}{24}.