MathDB
2013 ToT Fall Senior O p2 3 similar triangles on sides of a triangle

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March 22, 2020
geometrysimilar trianglesparallelogram

Problem Statement

On the sides of triangle ABCABC, three similar triangles are constructed with triangle YBAYBA and triangle ZACZAC in the exterior and triangle XBCXBC in the interior. (Above, the vertices of the triangles are ordered so that the similarities take vertices to corresponding vertices, for example, the similarity between triangle YBAYBA and triangle ZACZAC takes YY to Z,BZ, B to AA and AA to CC). Prove that AYXZAYXZ is a parallelogram