Geometry Problem 1273

Elements: Circle, Tangent, Secant, Midpoint, Isogonal Lines, Congruent Angles

In the figure, AB and AC are tangents to a circle O at B and C, respectively. D is a point on arc BC and AD extended meets the chord BC at E. If M is the midpoint of BC, prove that the angles BDM and EDC are congruent.

See also:
Geometry problem 1271 in motion. 

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