One corner of the triangle is 20 degrees larger than the other and 20 degrees less than the third. Find the smaller corner.

To solve the problem, we will compose and solve a linear equation. And let’s start by introducing alternately. So, let one of the angles be x °, then the other two can be written as (x – 20) ° and (x + 20) °.

We apply the theorem on the sum of the angles of a triangle to compose the equation; it says that the sum of all the angles of a triangle is 180 °.

We get a linear equation with one variable:

x + (x – 20) + (x + 20) = 180;

x + x – 20 + x + 20 = 180;

3x = 180;

x = 180/3;

x = 60 °.

60 ° – 20 ° = 40 ° is the degree measure of the smaller angle of the triangle.

Answer: 40 °.