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MathNet 2019-part-07 — 184 problems (EN–VI) Question 36

Math Olympiad Vault · MathNet 2019-part-07 — 184 problems (EN–VI)

Question 36

Let $I$ be the incenter and $H$ the orthocenter of triangle $ABC$. A point $K$ in the plane satisfies
$$
AH + AK = BH + BK = CH + CK.
$$
Prove that $H$, $I$, $K$ are collinear.