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MathNet 2020 — Math Olympiad Vault — Part 03 Question 146

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 03

Question 146

Let $ABC$ be a triangle with its circumcircle, and suppose $AC\lt AB$. A point $D\ne A$ varies on the minor arc $AC$. Let $E$ be the reflection of $A$ across the internal angle bisector of $\angle BDC$. Prove that $DE$ passes through a fixed point independent of $D$.

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