[tex]\text{Supplementary angles adds up to 180 degree.}\\\text{Given that the angles are x and x/4. As they are supplementary}\\\text{ they add up to 180 degrees}\\\\\\ x+\dfrac{x}{4}=180\\\\\\\dfrac{4x+x}{4}=180\\\\\\5x=720\\\\\\x=\dfrac{720}{5}\\\\\\\boxed{x=144}[/tex]
