Explanation:
when a line intersects 2 or more parallel lines, it must have the same intersection angles with each of the parallel lines. otherwise the lines are not parallel after all, because parallel lines imitate each other's properties and behaviors exactly except for the actual location.
so,
angle 1 = 135°
the intersection angles between 2 lines must be the same in each side of each line, they are just left-right mirrored.
so,
angle 2 = angle 1 = 135°