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MathNet 2026 — Part 04 Question 19

Math Olympiad Vault · MathNet 2026 — Part 04

Question 19

Let $ABC$ a triangle and $\omega$ his circle inscribed. we note $P, Q, R$ the contact points of $\omega$ with $(BC), (CA)$ and $(AB)$. A circle passing through $B$ and $C$ is tangent in $X$ à $\omega$, a circle passing through $C$ and $A$ is tangent in $Y$ à $\omega$ and a circle passing through $A$ and $B$ is tangent in $Z$ à $\omega$. Show that the lines $(PX), (QY)$ and $(RZ)$ are concurrent.