Answer
$ 150^{\circ}$
Work Step by Step
Given angle = $ -210^{\circ}$
In figure 24, we can see that terminal position corresponding to $ -210^{\circ}$ from positive side is $ 150^{\circ}$
Therefore angle coterminal with $ -210^{\circ}$ between $0^{\circ}$ and $360^{\circ}$ = $ 150^{\circ}$
Cross checking-
Angle coterminal with $ -210^{\circ}$ between $0^{\circ}$ and $360^{\circ}$
= $ -210^{\circ} + 360$
= $ 150^{\circ}$
