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MathNet 2013 Question 5

Math Olympiad Vault · MathNet 2013

Question 5

Let $ABCD$ be a cyclic quadrilateral with $BC = CD$, let $\omega$ be the circle centered at $C$ tangent to $BD$, and let $I$ be the incenter of $ABD$. Show that the line through $I$ parallel to $AB$ is tangent to $\omega$.