Let x be one of the angles. We know that the other one is one third of it and we know that they are supplementary, then we have that:
[tex]\begin{gathered} x+\frac{1}{3}x=180 \\ \frac{4}{3}x=180 \\ x=\frac{180}{\frac{4}{3}} \\ x=135 \end{gathered}[/tex]Once we know the value of x we divide by three to find the second angle:
[tex]\frac{135}{3}=45[/tex]Therefore one angle is 45° and the other is 135°
