MathDB
congruent quadrilaterals

Source: bmo 1984

April 23, 2007
geometryparallelogramcircumcircleratiogeometric transformationhomothetyreflection

Problem Statement

Let ABCDABCD be a cyclic quadrilateral and let HA,HB,HC,HDH_{A}, H_{B}, H_{C}, H_{D} be the orthocenters of the triangles BCDBCD, CDACDA, DABDAB and ABCABC respectively. Show that the quadrilaterals ABCDABCD and HAHBHCHDH_{A}H_{B}H_{C}H_{D} are congruent.
Back to ProblemsView on AoPS