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IMO 1970 — Shortlisted problems Question 6

IMO Shortlist · IMO 1970 — Shortlisted problems

Question 6

(FRA 1) In the triangle $ABC$ let $B'$ and $C'$ be the midpoints of the sides $AC$ and $AB$ respectively and $H$ the foot of the altitude passing through the vertex $A$. Prove that the circumcircles of the triangles $AB'C'$, $BC'H$, and $B'CH$ have a common point $I$ and that the line $HI$ passes through the midpoint of the segment $B'C'$.