In triangle ABC, angle A is 78 degrees, and angle B is 3 times less. You need angle C of triangle ABC.

Let’s find the angle B, which is three times less than the angle A:
78/3 = 26 ° – angle B.
The angles of a triangle add up to 180 °. Knowing the two corners of the triangle, it is easy to find the third.
180 ° – (78 ° + 26 °) = 180 ° – 104 ° = 76 ° – angle С of the triangle ABC.
Answer: the degree measure of the angle C is 76 °.