Answer :
[tex]\begin{gathered} \pi\text{radian}=180\degree \\ \\ -280\degree\cdot\frac{\pi\text{radian}}{180\degree}=_{}-\frac{280}{180}\pi radians \\ \\ \text{Symplify:} \\ \\ =\frac{14}{9}\pi\text{radians} \end{gathered}[/tex]