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NM tangent to incircle of ABC, 2 circumcircles related

Source: IX - Mathematics Regional Olympiad of Mexico Northeast 2009 P3

September 17, 2022
geometryincircletangentcircumcircle

Problem Statement

The incircle of triangle ABC\vartriangle ABC is tangent to side ABAB at point PP and to side BCBC at point QQ. The circle passing through points A,P,QA,P,Q intersects line BCBC a second time at MM and the circle passes through the points C,P,QC,P,Q and cuts the line ABAB a second time at pointN N. Prove that NMNM is tangent to the incircle of ABCABC.