Find the angles of a parallelogram if the difference between its two angles is 40 degrees.

Let us denote by the variable x the degree value of the smaller of the angles of the indicated parallelogram.
Therefore, according to the condition of the problem, the degree value of the larger of the angles of the parallelogram we can express through (x + 40).
Knowing that the sum of the angles of the parallelogram adjacent to one side is by definition equal to 180 °, we compose an equation and determine the degree values of these angles of the parallelogram:
x + (x + 40) = 180;
2x = 140;
x = 70;
180 – 70 = 110.
Answer: The degree value of the smaller angle is 70 °, the larger one is 110 °.