MathDB
Albanian TST 2014 3rd problem

Source:

April 21, 2014
geometry proposedgeometry

Problem Statement

From the point PP outside a circle ω\omega with center OO draw the tangents PAPA and PBPB where AA and BB belong to ω\omega.In a random point MM in the chord ABAB we draw the perpendicular to OMOM, which intersects PAPA and PBPB in CC and DD. Prove that MM is the midpoint CDCD.