Answer:
Step-by-step explanation:
Angles 1 and 5 are in corresponding positions, so since A and B are parallel to each other, angles 1 and 5 are also congruent. If they are congruent, then that have the exact same measure. That means that if the sum of them is 100, each one has a measure of 50 degrees.
Angle 4 is vertical to angle 1, so that means that angles 1 and 4 are congruent. If angle 1 measures 50, then so does angle 4.
