IMO 1987 LL TUR61

Let PQ be a line segment of constant length \lambda taken on the

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IMO 1987 LL TUR61

Origin: TUR

Problem

Let PQ be a line segment of constant length \lambda taken on the side BC of a triangle ABC with the order B, P, Q, C, and let the lines through P and Q parallel to the lateral sides meet AC at P1 and Q1 and AB at P2 and Q2 respectively. Prove that the sum of the areas of the trapezoids PQQ1P1 and PQQ2P2 is independent of the position of PQ on BC.