Hey there!!
Angle 2 is given by 12 x and hence angle 4 would become 12x due to vertically opposite angle.
Angle 1 is given by 3x and hence, angle 4 + angle 1 = 180 ( straight angles )
... 12x + 3x = 180
... 15x = 180
... x = 12
Angle 4 = 12x
... 12 ( 12 )
... 144°
Hope my answer helps!!
