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MathNet 2023-part-01 — 191 problems (EN–VI) Question 46

Math Olympiad Vault · MathNet 2023-part-01 — 191 problems (EN–VI)

Question 46

Let $ABCD$ be a rhombus with $\angle BAD \lt 90^\circ$. The circle passing through $D$ with center $A$ intersects the line $CD$ a second time in point $E$. Let $S$ be the intersection of the lines $BE$ and $AC$.
Prove that the points $A, S, D$ and $E$ lie on a circle.

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