Find the angles of a parallelogram if one angle is 4 times greater than the other.

Given:
ABCE – parallelogram,
angle A = 4 * angle B.
Find the degree measures of the angles of the parallelogram ABCE: angle A, angle B, angle C, angle E -?
Decision:
Consider a parallelogram ABCE. Its opposite angles are equal to each other, then angle A = angle C, angle B = angle E.
Let the degree measure of angle B be equal to x degrees, then the degree measure of angle A is equal to 4 * x degrees. We know that the sum of the degree measures of a parallelogram is 360 degrees. Let’s make the equation:
x + x + 4 * x + 4 * x = 360;
x * (1 + 1 + 4 + 4) = 360;
x * 10 = 360;
x = 360: 10;
x = 36 degrees – the degree measure of the angle B;
36 * 4 = 144 degrees – the degree measure of angle A.
Answer: 144 degrees; 36 degrees; 144 degrees; 36 degrees.