MathDB
2015 JBMO Shortlist G2

Source: 2015 JBMO Shortlist G2

October 8, 2017
geometryJBMO

Problem Statement

The point P{P} is outside the circle Ω{\Omega}. Two tangent lines, passing from the point P{P} touch the circle Ω{\Omega} at the points A{A} and B{B}. The medianAM(MBP){AM \left(M\in BP\right)} intersects the circle Ω{\Omega} at the point C{C} and the line PC{PC} intersects again the circle Ω{\Omega} at the point D{D}. Prove that the lines AD{AD} and BP{BP} are parallel.
(Moldova)