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MathNet 2024-part-01 — 168 problems (EN–VI) Question 1

Math Olympiad Vault · MathNet 2024-part-01 — 168 problems (EN–VI)

Question 1

Let $ABC$ be an acute triangle. Let $D$ be a point on side $AB$ and $E$ be a point on side $AC$ such that lines $BC$ and $DE$ are parallel. Let $X$ be an interior point of $BCED$. Suppose rays $DX$ and $EX$ meet side $BC$ at points $P$ and $Q$, respectively, such that both $P$ and $Q$ lie between $B$ and $C$. Suppose that the circumcircles of triangles $BQX$ and $CPX$ intersect at a point $Y \neq X$. Prove that points $A$, $X$, and $Y$ are collinear.