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IMO 1986 — Shortlisted problems Question 14

IMO Shortlist · IMO 1986 — Shortlisted problems

Question 14

(IRE 1) The circle inscribed in a triangle $ABC$ touches the sides $BC,CA,AB$ in $D,E,F$, respectively, and $X,Y,Z$ are the midpoints of $EF,FD,DE$, respectively. Prove that the centers of the inscribed circle and of the circles around $XYZ$ and $ABC$ are collinear.