Answer
$9$
Work Step by Step
We know that $\tan$ has a period of $\pi$, hence $\tan(\theta)=\tan(\theta+k\pi)$ where $k$ is an integer.
Therefore,
$\tan(\theta)+\tan(\theta+\pi)+\tan(\theta+2\pi)\\
=\tan(\theta)+\tan(\theta)+\tan(\theta)\\
=3+3+3\\
=9$
