what is the reference angle for a 240° angle?\n30°\n60°\n180°\n270°

Answer:

B. $60^{\circ}$

Explanation:

Step1: Determine the quadrant

The angle $240^{\circ}$ is in the third - quadrant since $180^{\circ}<240^{\circ}<270^{\circ}$.

Step2: Use the reference - angle formula for third - quadrant

For an angle $\theta$ in the third - quadrant, the reference angle $\theta_{r}=\theta - 180^{\circ}$. So, $\theta_{r}=240^{\circ}-180^{\circ}=60^{\circ}$.