Answer
$120^o + 360^o(n)$, for all integers $n$.
Work Step by Step
RECALL:
Adding multiples of $360^o$ to an angle $\theta$ gives angles that are coterminal with $\theta$.
Thus, the angles that are coterminal with $120^o$ are:
$120^o + 360^o(n)$, for all integers $n$.
