MathDB
A simple geometry

Source: Indian RMO 1999 Problem 3

October 26, 2005
geometrycircumcircle

Problem Statement

Let ABCDABCD be a square and M,NM,N points on sides AB,BCAB, BC respectively such that MDN=45\angle MDN = 45^{\circ}. If RR is the midpoint of MNMN show that RP=RQRP =RQ where P,QP,Q are points of intersection of ACAC with the lines MD,NDMD, ND.