MathDB
collinear wanted, 2 parallelograms related

Source: Champions Tournament (Ukraine) - Турнір чемпіонів - 2010 Seniors p3

September 6, 2020
geometryparallelogramcollinearChampions Tournament

Problem Statement

On the sides ABAB and BCBC arbitrarily mark points MM and NN, respectively. Let PP be the point of intersection of segments ANAN and BMBM. In addition, we note the points QQ and RR such that quadrilaterals MCNQMCNQ and ACBRACBR are parallelograms. Prove that the points P,QP,Q and RR lie on one line.