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MathNet 2020 — Math Olympiad Vault — Part 02 Question 128

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 02

Question 128

Let $ABC$ be a triangle inscribed in a circle $\omega$ and $\ell$ be the tangent to $\omega$ at $A$. The line through $B$ parallel to $AC$ meets $\ell$ at $P$, and the line through $C$ parallel to $AB$ meets $\ell$ at $Q$. The circumcircles of $ABP$ and $ACQ$ meet at $S \neq A$. Show that $AS$ bisects $BC$.