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MathNet 2021 — Part 07 Question 65

Math Olympiad Vault · MathNet 2021 — Part 07

Question 65

Let $ABC$ be an isosceles triangle with $AB = AC$. Point $D$ lies on side $AC$ such that $BD$ is the angle bisector of $\angle ABC$. Point $E$ lies on side $BC$ between $B$ and $C$ such that $BE = CD$. Prove that $DE$ is parallel to $AB$.