Supplementary angles are two angles that add to 180 degrees.
The equation is 4x + 5x = 180.
(combine like terms and simplify) 9x=180
180/9=20
so x = 20
So that would mean 4x= 80.
The smaller angle is equal to 80. Since supplementary angles add up to 180, you have a clue as to what the larger angle measures to.
