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

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

Given:
triangle ABC,
degree measure angle ABC = 40 degrees,
degree measure angle CAB = 3 * angle ABC.
Find the degree measure of the angle ACB -?
Decision:
1) Consider the triangle ABC.
angle CAB = 3 * angle ABC;
angle CAB = 3 * 40;
CAB angle = 120 degrees
2) We know that the sum of the degree measures of any triangle is 180 degrees. Hence:
angle ABC + angle CAB + angle ACB = 180;
angle ACB = 180 – (angle ABC + angle CAB);
angle ACB = 180 – (40 + 120);
angle ACB = 180 – 160;
angle ACB = 20 degrees.
Answer: ACB angle = 20 degrees.