In triangle ABC, angle A = 54 °, angle B = 60 °, find the degree measure of angle C.

Given:
triangle ABC,
angle A = 54 degrees,
angle B = 60 degrees.
Find the degree measure of the angle C -?
Decision:
Consider a triangle ABC. We know that the sum of the degree measures of the angles of any triangle is 180 degrees. Hence:
angle A + angle B + angle C = 180 (substitute 54 degrees instead of angle A, and 60 degrees instead of angle B);
54 + 60 + angle C = 180;
114 + angle C = 180;
angle C = 180 – 114;
angle C = 66 degrees.
Answer: 66 degrees.