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MathNet 2004 — Part 02 Question 2

Math Olympiad Vault · MathNet 2004 — Part 02

Question 2

In the interiors of the sides $AB$, $BC$, $CA$ of a given triangle $ABC$, points $K$, $L$ and $M$, respectively, are given such that
$$
\frac{|AK|}{|KB|} = \frac{|BL|}{|LC|} = \frac{|CM|}{|MA|}
$$
Show that the triangles $ABC$ and $KLM$ have a common orthocenter if and only if the triangle $ABC$ is equilateral.