MathDB
perpendicularity starting with a rectangle, danube junior 2013

Source: Danube 2013 Junior P4

September 7, 2018
geometryrectangleperpendicular

Problem Statement

Let ABCDABCD be a rectangle with ABBCAB \ne BC and the center the point OO. Perpendicular from OO on BDBD intersects lines ABAB and BCBC in points EE and FF respectively. Points MM and NN are midpoints of segments [CD][CD] and [AD][AD] respectively. Prove that FMENFM \perp EN .