Geometry, Theorems and Problems

 Problem 245. Parallelogram with Equilateral triangles. Congruence

In the figure, equilateral triangles BCE and CDF are constructed on the sides BC and CD of a parallelogram ABCD. Prove that AEF is an equilateral triangle. View or post a solution.

Elearning 245: Parallelogram and equiilateral triangles 

Auxiliary Line: A line, ray, or segment added to a diagram to help in a proof or solution.

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