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MathNet 2008-part-04 — 165 problems (EN–VI) Question 50

Math Olympiad Vault · MathNet 2008-part-04 — 165 problems (EN–VI)

Question 50

Given an acute triangle $ABC$, determine for which points of its interior the following inequalities hold:
$$
1 \leq \frac{\angle APB}{\angle ACB} \leq 2, \quad 1 \leq \frac{\angle BPC}{\angle BAC} \leq 2 \quad \text{and} \quad 1 \leq \frac{\angle CPA}{\angle CBA} \leq 2
$$