Angle 1 is equal to angle 2, angle 3 is 120 degrees, find angle 4

Two parallel lines m and n and two secants intersecting at one point C form angles 1, 2, 3 and 4, which are characterized by the condition of the problem.

And the condition says that the degree measure of angles 1 and 2 are equal to each other, it is also known that angle 3 = 120 °.

And we need to find the degree measure of the angle 4.

Solution:

the lines m and n are parallel, since ∠ 1 = ∠ 2 and cross-lying ∠ 3 = ∠ 4 = 120 °, since they lie with parallel lines m and n and the secant BC.

We can write down the answer.

Answer: 120 ° degree measure of angle 4.