Answer
$ 30^{\circ}$ and $210^{\circ}$.
Work Step by Step
$\tan \theta=\frac{\sqrt 3}{3}=\frac{1}{\sqrt 3}$
The value of $\tan \theta$ is positive, so $\theta$ may lie in either quadrant I or III.
We know that $\tan 30^{\circ}=\frac{1}{\sqrt 3}$.
$30^{\circ}$ is one possible value of $\theta$.
Now, $\tan\theta=\tan(180^{\circ}+\theta)\implies $
$\tan 30^{\circ}= \tan(180^{\circ}+30^{\circ})=\tan 210^{\circ}$
$210^{\circ}$ is the value of $\theta$ in the third quadrant.
The values of $\theta$ are $ 30^{\circ}$ and $210^{\circ}$.
