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APMO 1996 - Asian Pacific Mathematics Olympiad Question 1

APMO · APMO 1996 - Asian Pacific Mathematics Olympiad

Question 1

Let $ABCD$ be a quadrilateral with $AB=BC=CD=DA$. Let $MN$ and $PQ$ be segments perpendicular to diagonal $BD$, at distance $d\gt BD/2$ from each other, where $M\in AD$, $N\in DC$, $P\in AB$, $Q\in BC$. Show that the perimeter of hexagon $AMNCQP$ is independent of the positions of $MN,PQ$ provided their distance remains constant.

Question illustration