starting with 2 points on sides of an angle, midpoints given and wanted
Source: 2007 Sharygin Geometry Olympiad Correspondence Round P16
April 27, 2019
geometryanglemidpoint
Problem Statement
On two sides of an angle, points are chosen. The midpoint of the segment belongs to two lines such that one of them meets the sides of the angle at points , and the other at points . The lines and meet at points and . Prove that is the midpoint of .