MathDB
Show that CM is perpendicular to PQ with circumcenter M

Source: Turkey IMO TST 1993 #2

July 7, 2011
geometrycircumcirclegeometry unsolved

Problem Statement

Let MM be the circumcenter of an acute-angled triangle ABCABC. The circumcircle of triangle BMABMA intersects BCBC at PP and ACAC at QQ. Show that CMPQCM \perp PQ.