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MathNet 2020 — Math Olympiad Vault — Part 03 Question 122

Math Olympiad Vault · MathNet 2020 — Math Olympiad Vault — Part 03

Question 122

In an acute triangle $ABC$, the centre of the incircle is $I$, and $|AC| + |AI| = |BC|$. Prove that $\angle BAC = 2\angle ABC$.