Proportionally? Not sure. But here is a way to find out the value of x
50° + 2x+40 +4x+8 = 180°
Combine like terms
50°+ 6x + 48=180
(now subtract 50° from both sides)
6x + 48 = 130°
(now subtract 48 from both sides
6x=82°
x= 13.6666667° (repeating decimal)
The supplement of a 9 degree angle is 171 degrees.