In triangle ABC and A1B1C1 angle A = 50 degrees angle C = 60 degrees angle C1 = 60 degrees

In triangle ABC and A1B1C1 angle A = 50 degrees angle C = 60 degrees angle C1 = 60 degrees angle B1 = 70 degrees prove that triangle ABC is similar to triangle A1B1C1.

Angle C = angle C1 = 60 degrees. Find the angle B of the triangle ABC. The angles in a triangle add up to 180 degrees. This means that angle B = 180 – angle A – angle C = 180 – 50 – 60 = 70. We got that angle B = angle B1 = 70. So, two angles of one triangle are equal to two angles of another triangle. By the first sign of similarity, triangles ABC and A1B1C1 are similar