Supplementary = equal to 180 degrees.
We can set up an equation.
2x + x = 180
Combine like-terms:
3x = 180
Divide both sides by 3 to isolate the x.
x = 60.
So one angle is 60 degrees and since the other one is twice of x, it is 120 degrees. If you add 120 and 60 degrees, you should get 180 degrees.
Nevertheless, the measures of the angles are 60 and 120 degrees.
