Answer:
[tex]\frac{\sqrt{3}}{2}[/tex]
Step-by-step explanation:
Sine is positive in the second quadrant, so:
[tex]\sin \frac{240^{\circ}}{2}=\sqrt{\frac{1-\cos 240^{\circ}}{2}} \\ \\ =\sqrt{\frac{1.5}{2}} \\ \\ =\sqrt{3/4} \\ \\ =\frac{\sqrt{3}}{2}[/tex]
