MathDB
concyclic points wanted, parallels and circumcircle given

Source: Tuymaada Junior 2007 p7

May 12, 2019
geometrycircumcircleConcyclicparallel

Problem Statement

On the AB AB side of the triangle ABC ABC , points X X and Y Y are chosen, on the side of AC AC is a point of Z Z , and on the side of BC BC is a point of T T . Wherein XZBC XZ \parallel BC , YTAC YT \parallel AC . Line TZ TZ intersects the circumscribed circle of triangle ABC ABC at points D D and E E . Prove that points X X , Y Y , D D and E E lie on the same circle.