Since we're working on a circumference, the sum of all the angles must be 360°
This way,
[tex]85+3x+73+x+82=360[/tex]
Solving for x :
[tex]\begin{gathered} 85+3x+73+x+82=360 \\ \rightarrow240+4x=360 \\ \rightarrow4x=120 \\ \rightarrow x=\frac{120}{4} \\ \Rightarrow x=30 \end{gathered}[/tex]
