Niloy G. answered • 10/30/19

MD and Experienced HS Chemistry teacher, Specialize in Grades 6-12

You are correct, 1 would supplement 4. This is because angles 1 and 3 are equal due to them being corresponding angles. By the same logic, 2 and 4 are corresponding angles and therefore equal. Thus since 1+2 = 180, 1+4 = 180