MathDB
Turkey TST 2009 Quadrilateral

Source: Turkey TST 2009, Problem 2

April 5, 2009
trigonometrygeometry unsolvedgeometry

Problem Statement

Quadrilateral ABCD ABCD has an inscribed circle which centered at O O with radius r r. AB AB intersects CD CD at P P; AD AD intersects BC BC at Q Q and the diagonals AC AC and BD BD intersects each other at K K. If the distance from O O to the line PQ PQ is k k, prove that OK\cdot\ k \equal{} r^2.
Back to ProblemsView on AoPS