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MathNet 2017-part-01 — 176 problems (EN–VI) Question 37

Math Olympiad Vault · MathNet 2017-part-01 — 176 problems (EN–VI)

Question 37

Let $ABCD$ be a cyclic quadrilateral with perpendicular diagonals and circumcenter $O$. Let $g$ be the line obtained by reflection of the diagonal $AC$ about the angle bisector of $\angle BAD$.
*Prove that the point $O$ lies on the line $g$.*