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MathNet 2009-part-01 — 175 problems (EN–VI) Question 156

Math Olympiad Vault · MathNet 2009-part-01 — 175 problems (EN–VI)

Question 156

Given a circle $k$ and its chord $AB$ which is not the diameter. Let $C$ be any point inside the longer arc of $k$. We denote by $K$ and $L$ the reflections of $A$ and $B$ with respect to the axes $BC$ and $AC$. Prove that the distance of the midpoints of the line segments $KL$ and $AB$ is independent of the location of the point $C$.