MathDB
trapezoid, 4 perpendiculars, collinear ? (2017 HOMC Junior Q14)

Source:

August 3, 2019
geometrytrapezoidcollinearcollinearityperpendicular

Problem Statement

Given trapezoid ABCDABCD with bases ABCDAB \parallel CD (AB<CDAB < CD). Let OO be the intersection of ACAC and BDBD. Two straight lines from DD and CC are perpendicular to ACAC and BDBD intersect at EE , i.e. CEBDCE \perp BD and DEACDE \perp AC . By analogy, AFBDAF \perp BD and BFACBF \perp AC . Are three points E,O,FE , O, F located on the same line?