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MathNet 2019-part-06 — 184 problems (EN–VI) Question 96

Math Olympiad Vault · MathNet 2019-part-06 — 184 problems (EN–VI)

Question 96

A convex quadrilateral $A B C D$ is circumscribed about a circle $k$. The lines $A D$ and $B C$ meet at the point $P$, and the circles circumscribed about $\triangle P A B$ and $\triangle P C D$ meet at the point $X$. Prove that the tangents from the point $X$ to the circle $k$ make equal angles with the lines $A X$ and $C X$.