In the figure below, given a triangle
ABC, line DEF parallel to AC and line FGM parallel to AB. If O,
O_{1}, O_{2}, and O_{3}, are the
incenters of triangles ABC, DBE, FGE, and MGC respectively,
prove that the quadrilateral OO_{1}O_{2}O_{3}
is a parallelogram.
View or post a solution.
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