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MathNet 2015-part-01 — 191 problems (EN–VI) Question 50

Math Olympiad Vault · MathNet 2015-part-01 — 191 problems (EN–VI)

Question 50

Let $\triangle ABC$ be a triangle with incenter $I$ and circumcircle $(\omega)$. The lines $AI, BI, CI$ intersect $(\omega)$ for second time at the points $D, E, F$ respectively. The parallel lines through $I$ to the sides $BC, AC, AB$ intersect the lines $EF, DF, DE$ at the points $K, L, M$ respectively. Prove that the points $K, L, M$ are collinear.