In triangle ABC, the degree measure of the angle ABC is 40 *, and the degree measure

In triangle ABC, the degree measure of the angle ABC is 40 *, and the degree measure of the angle CAB is 3 times greater. find the degree measure of the angle ACB.

1. Let us denote the degree measure of the angle ABC through B, the degree measure of the angle CAB through A, and the degree measure of the angle ACB through C. By the condition of the problem, B = 40 °.

2. Also, according to the condition of the problem, A = 3 * B = 3 * 40 ° = 120 °.

3. The sum of the interior angles of the triangle is 180 °. That is, A + B + C = 180 °.

4. Hence C = 180 ° – A – B = 180 ° – 120 ° – 40 ° = 20 °.

Answer: the degree measure of the ACB angle is 20 °.