MathDB
P is a point moving on Ω.

Source: KöMaL, May 2020

March 12, 2021
geometryTangentscirclesincenterconcurrentreflection

Problem Statement

Two circles are given in the plane, Ω\Omega and inside it ω\omega. The center of ω\omega is II. PP is a point moving on Ω\Omega. The second intersection of the tangents from PP to ω\omega and circle Ω\Omega are QQ and R.R. The second intersection of circle IQRIQR and lines PIPI, PQPQ and PRPR are JJ, SS and T,T, respectively. The reflection of point JJ across line STST is K.K. Prove that lines PKPK are concurrent.