MathDB
Find the locus of circumcenter.

Source: Mongolian TST 2008 day4 problem3

May 28, 2008
geometrycircumcirclepower of a pointradical axisgeometry proposed

Problem Statement

Let Ω \Omega is circle with radius R R and center O O. Let ω \omega is a circle inside of the Ω \Omega with center I I radius r r. X X is variable point of ω \omega and tangent line of ω \omega pass through X X intersect the circle Ω \Omega at points A,B A,B. A line pass through X X perpendicular with AI AI intersect ω \omega at Y Y distinct with X X.Let point C C is symmetric to the point I I with respect to the line XY XY.Find the locus of circumcenter of triangle ABC ABC when X X varies on ω \omega