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MathNet 2018-part-04 — 181 problems (EN–VI) Question 50

Math Olympiad Vault · MathNet 2018-part-04 — 181 problems (EN–VI)

Question 50

Let $\triangle ABC$ be a triangle and let $\omega$ be its $A$-excircle (excircle opposite vertex $A$). Let $D, E, F$ be the points where $\omega$ touches the lines $BC, CA, AB$, respectively. The circle $AEF$ crosses the line $BC$ at $P$ and $Q$. Let $M$ be the midpoint of the line segment $AD$. Prove that the circles $\omega$ and $MPQ$ are tangent.