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MathNet 2026 — Part 06 Question 115

Math Olympiad Vault · MathNet 2026 — Part 06

Question 115

Suppose $ABC$ is an equilateral triangle whose circumcircle $\Gamma$ has radius $1$. Prove that if $P$ is within or on $\Gamma$, then the product $|PA| \cdot |PB| \cdot |PC|$ does not exceed $2$. Also determine the points $P$ for which the product is equal to $2$.