What are the angles of an isosceles trapezoid if it is known that the difference between the opposite angles is 40 degrees?

Given:
ABCE – isosceles trapezoid,
Angle B – angle A = 40 degrees.
Find the degree measures of the angles of an isosceles trapezoid ABCE, that is, angle A, angle B, angle C, angle E -?
Decision:
Consider an isosceles trapezoid ABCE. The angles at the base are equal, that is, angle A = angle E, angle B = angle C.
Let the angle A = x degrees, then the angle B = x + 40 degrees. The bases of the trapezoid ABCE – the segments BC and AE are parallel. Then angle A + angle B = 180 degrees. Let’s make the equation:
x + x + 40 = 180;
x + x = 140;
2 * x = 140;
x = 140: 2;
x = 70 degrees – the degree measure of the angle A;
70 + 40 = 110 degrees is the degree measure of angle B.
Answer: 70 degrees; 110 degrees; 110 degrees; 70 degrees.