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MathNet 2021 — Part 01 Question 89

Math Olympiad Vault · MathNet 2021 — Part 01

Question 89

Let $P$ be a point on segment $BC$ of triangle $\triangle ABC$. Let $O_1$ and $O_2$ be the respective circumcenters of $\triangle ABP$ and $\triangle ACP$. Given $BC = O_1O_2$, show that some angle of $\triangle ABC$ is more than $75^\circ$.