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MathNet 2026 — Part 03 Question 36

Math Olympiad Vault · MathNet 2026 — Part 03

Question 36

Let $ABC$ be the right-angled isosceles triangle whose equal sides have length $1$. $P$ is a point on the hypotenuse, and the feet of the perpendiculars from $P$ to the other sides are $Q$ and $R$. Consider the areas of the triangles $APQ$ and $PBR$, and the area of the rectangle $QCRP$. Prove that regardless of how $P$ is chosen, the largest of these three areas is at least $2/9$.

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