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MathNet 2015-part-02 — 191 problems (EN–VI) Question 182

Math Olympiad Vault · MathNet 2015-part-02 — 191 problems (EN–VI)

Question 182

Let $ABC$ be a triangle with three acute angles, and $P$ the foot of the altitude from $A$. Let $I_{1}$ and $I_{2}$ be the incenters of $ABP$ and $ACP$. The incircle of $ABC$ touches $[BC]$ at $D$. What are the angles of the triangle $I_{1}I_{2}D$?

Question illustration