In the given figure
∵ There are 2 parallel lines intersected by a transversal
∴ < 1 and < 7 are alternate exterior angles
∴ m<1 = m< 7
∵ m<7 = 37 degrees
∴ m<1 = 37 degrees
∵ m<1 + m<4 = 180 degrees because they formed a straight line
∴ 37 + m<4 = 180
→ Subtract 37 from both sides to find m<4
∵ 37 - 37 + m<4 = 180 - 37
∴ m<4 = 143 degrees
