In a triangle MOK, the angle O = 76 degrees, and the angle M is 3 times less than the outer angle

In a triangle MOK, the angle O = 76 degrees, and the angle M is 3 times less than the outer angle at the vertex K. Find the unknown angles of the triangle.

Let the angle M be equal to x, then the external angle at the vertex K is equal to 3x. Because the sum of adjacent angles is 180 degrees, then the angle K = 180-3x.
The sum of the angles of a triangle is 180 degrees, which means angle O + angle M + angle K = 180;
76 + x + 180-3x = 180;
76-2x = 0;
2x = 76;
x = 76/2 = 38.
Therefore, the angle M is 38 degrees, the angle K = 180-3x = 180-3 * 38 = 180-114 = 66 degrees.