MathDB
Regular 2009-gon - TT 2009 Senior-O4

Source:

September 3, 2010
geometrygeometric transformationreflectiontrigonometrygeometry unsolved

Problem Statement

A point is chosen on each side of a regular 20092009-gon. Let SS be the area of the 20092009-gon with vertices at these points. For each of the chosen points, reflect it across the midpoint of its side. Prove that the 20092009-gon with vertices at the images of these reflections also has area S.S.
(4 points)