Given:
To convert a given degree into radians.
The formula tp convert degree to radian is
[tex]\begin{gathered} \text{Radian}=\frac{\pi}{180}\times degree \\ \text{Radian}=\frac{\pi}{180}\times80 \\ \text{Radian=}\frac{\pi}{9}\times4 \\ \text{Radian}=\frac{4\pi}{9} \end{gathered}[/tex]Hence option d) is the correct answer.
