MathDB
Equality of perimeters

Source: VII Centroamerican and Caribbean Olympiad 2005, Problem 5

July 29, 2005
geometryperimetertrigonometryparallelogramangle bisectorgeometry proposed

Problem Statement

Let ABCABC be a triangle, HH the orthocenter and MM the midpoint of ACAC. Let \ell be the parallel through MM to the bisector of AHC\angle AHC. Prove that \ell divides the triangle in two parts of equal perimeters. Pedro Marrone, Panamá