Ibero American 2012 - Problem 1
Source: Ibero American 2012
October 2, 2012
geometryparallelogramgeometry proposed
Problem Statement
Let be a rectangle. Construct equilateral triangles and , in such a way that both of these triangles share some of their interior points with some interior points of the rectangle. Line intersects line on , and line intersects line on . Prove that triangle is equilateral.