MathDB
easy geometry

Source: Iran team selection test third exam p1

June 4, 2015
geometryradical axis

Problem Statement

Point AA is outside of a given circle ω\omega. Let the tangents from AA to ω\omega meet ω\omega at S,TS, T points X,YX, Y are midpoints of AT,ASAT, AS let the tangent from XX to ω\omega meet ω\omega at RTR\neq T. points P,QP, Q are midpoints of XT,XRXT, XR let XYPQ=K,SXTK=LXY\cap PQ=K, SX\cap TK=L prove that quadrilateral KRLQKRLQ is cyclic.