MathDB
perpendicular segments

Source: Problem 1, Polish NO 1992

October 1, 2005
geometrycircumcirclegeometry solved

Problem Statement

Segments ACAC and BDBD meet at PP, and PA=PD|PA| = |PD|, PB=PC|PB| = |PC|. OO is the circumcenter of the triangle PABPAB. Show that OPOP and CDCD are perpendicular.