convex equilateral pentagon
Source: Bundeswettbewerb Mathematik 1992, round two, problem 3
June 19, 2004
trigonometrygeometry unsolvedgeometry
Problem Statement
Provided a convex equilateral pentagon. On every side of the pentagon We construct equilateral triangles which run through the interior of the pentagon. Prove that at least one of the triangles does not protrude the pentagon's boundary.