Answer:
see explanation
Step-by-step explanation:
Supplementary angles sum to 180° , then
x + y = 180 , that is
[tex]\frac{1}{3}[/tex] y + y = 180 ( multiply through by 3 to clear the fraction )
y + 3y = 540
4y = 540 ( divide both sides by 4 )
y = 135°
