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Find and construct the locus - ILL 1990 IND1

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September 18, 2010
geometry unsolvedgeometry

Problem Statement

Let ABCABC be an arbitrary acute triangle. Circle Γ\Gamma satisfies the following conditions: (i) Circle Γ\Gamma intersects all three sides of triangle ABC.ABC. (ii) In the convex hexagon formed by above six intersections, the three pairs of opposite sides are parallel respectively. (The hexagon maybe degenerate, that is, two or more vertices are coincide. In this case, "opposite sides are parallel" is defined through limit opinion.) Find the locus of the center of circle Γ\Gamma, and explain how to construct the locus.