IMO 2022 Shortlist G1
Let ABCDE be a convex pentagon such that BC “ DE. Assume there is a point T inside ABCDE with TB “ TD, TC “ TE and =TBA ...
Category: Geometry
Problem
Let ABCDE be a convex pentagon such that BC “ DE. Assume there is a point T inside ABCDE with TB “ TD, TC “ TE and =TBA “ =AET. Let lines CD and CT intersect line AB at points P and Q, respectively, and let lines CD and DT intersect line AE at points R and S, respectively. Assume that points P,B,A,Q and R,E,A,S respectively, are collinear and occur on their lines in this order. Prove that the points P, S, Q, R are concyclic. (Slovakia)