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Q,R,S are collinear

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September 6, 2010
Gausstrigonometrygeometry unsolvedgeometry

Problem Statement

Through a point PP within a triangle ABCABC the lines l,ml, m, and nn perpendicular respectively to AP,BP,CPAP,BP,CP are drawn. Prove that if ll intersects the line BCBC in QQ, mm intersects ACAC in RR, and nn intersects ABAB in SS, then the points Q,RQ, R, and SS are collinear.
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