IMO 2010 Shortlist G4
Let I be the incenter of a triangle ABC and Γ be its circumcircle. Let the line AI intersect Γ at a point D A. Let F a...
Category: Geometry
Problem
Let I be the incenter of a triangle ABC and Γ be its circumcircle. Let the line AI intersect Γ at a point D A. Let F and E be points on side BC and arc BDC respectively such that =BAF =CAE 1 =BAC. Finally, let G be the midpoint of the segment IF. Prove that the lines DG and EI intersect on Γ. (Hong Kong)