Explanation:
angle 2 is supplementary to angle 1 (together they have 180°).
so,
180 = angle 1 + angle 2 = 143 + angle 2
angle 2 = 37°
and when 2 lines intercept, the angles on both sides of either line are the same (just left-right mirrored, because they are upside-down views from each other).
so,
angle 3 = angle 1 = 143°
angle 4 = angle 2 = 37°