collinear wanted, 2 parallelograms related
Source: Champions Tournament (Ukraine) - Турнір чемпіонів - 2010 Seniors p3
September 6, 2020
geometryparallelogramcollinearChampions Tournament
Problem Statement
On the sides and arbitrarily mark points and , respectively. Let be the point of intersection of segments and . In addition, we note the points and such that quadrilaterals and are parallelograms. Prove that the points and lie on one line.