The figure below shows a point P inside (or outside) an equilateral triangle ABC. The points O1, O2, and O3 are the incenters of triangles APB, BPC and APC so that T1, T2, and T3 are tangency points. Prove that the lines T1O1, T2O2, and T3O3 are concurrent at a point D.
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Ten problems: 1411-1420
HTML5 and Dynamic Geometry
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