MathDB
segment equality

Source: baltic way, 2006

May 1, 2007
geometrycircumcircletrigonometryratiogeometric transformationreflectionpower of a point

Problem Statement

Let ABCABC be a triangle, let B1B_{1} be the midpoint of the side ABAB and C1C_{1} the midpoint of the side ACAC. Let PP be the point of intersection, other than AA, of the circumscribed circles around the triangles ABC1ABC_{1} and AB1CAB_{1}C. Let P1P_{1} be the point of intersection, other than AA, of the line APAP with the circumscribed circle around the triangle AB1C1AB_{1}C_{1}. Prove that 2AP=3AP12AP=3AP_{1}.