Answer
$240^{\circ}$
Work Step by Step
$\dfrac{-8\pi}{3}=-480 ^{\circ}$
Add $720 ^{\circ}$ (twice $360^{\circ}$) to $\dfrac{-8\pi}{3}=-480 ^{\circ}$ to find the positive co-terminal angle less than $360^{\circ}$.
$-480^{\circ} + 720^{\circ} =240^{\circ}=\dfrac{4\pi}{3}$
