Angle ABC = Angle A1B1C1. Points D and D1 are marked on their sides BC and B1C1.

Angle ABC = Angle A1B1C1. Points D and D1 are marked on their sides BC and B1C1. So BD = B1D1. Prove that treut ABD = treut A1B1D1.

Since triangles ABC and A1B1C1 are equal, then AB = A1B1, angle ABC = A1B1C1.

In triangles ABD and A1B1D1, angle ABD = A1B1D1, since points D and D1 lie on AC and A1C1, AB = A1B1, BD = B1D1 by condition, then triangles ABD and A1B1D1 are equal on two sides and the angle between them, which was required to prove …



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