MathDB
square inside a square, AE = BF = CG = DH - 2019 Ecuador Juniors (OMEC) L2 p4

Source:

October 24, 2022
geometrysquare

Problem Statement

Let ABCDABCD be a square. On the segments ABAB, BCBC, CDCD and DADA, choose points E,F,GE, F, G and HH, respectively, such that AE=BF=CG=DHAE = BF = CG = DH. Let PP be the intersection point of AFAF and DEDE, QQ be the intersection point of BGBG and AFAF, RR the intersection point of CHCH and BGBG, and SS the point of intersection of DEDE and CHCH. Prove that PQRSPQRS is a square.