FORMULA
[tex]\pi rad=180^0[/tex]
Convert 120 degree to radian by multiplying by pi and dividing by 180
[tex]\begin{gathered} \Rightarrow\frac{120\pi}{180} \\ \frac{2\pi}{3} \end{gathered}[/tex]
Given a negative angle, we add 360 to get its corresponding positive angle.
The answer can also be 2.09 rad
