In the diagram below, we have line AB is parallel to line CD, EF = FG, < BEF = 120 degrees + x degrees, and < AEG = x degrees. Find the value of x.
If angle BEF is 120 degrees, then angle FEG + anglex = 60 degrees. Using alternate interior angles, angle EFG is 120 degrees, and angle FEG = 60/2 = 30 degrees, so angle x = 30 degrees.
