Two angles are supplementary. one of them is three times the other. find the measure of the larger angle

Let x be the measure of the larger angle, and y the measure of the smaller one. We know that the sum of supplementary angles is allays 180°, so x+y=180. We also know that the smaller angle is three times the larger one, so x=3y. Now we can solve the system of equations to get our

Replacing equation 2 into equation 1:




Now that we know the value of our smaller angle, we just need to replace it into equation 2 to get the measure of our larger one:



We can conclude that the measure of the larger angle is 135°.