Answer :

The reference angle of the angle of -240º is of 60º.

The sine of the angle is given by:

[tex]\sin{-240^\circ} = \frac{\sqrt{3}}{2}[/tex]

How to find the reference angle of -240º?

The first step towards finding the equivalent angle of a negative angle is finding it's positive equivalent, adding 360º to it, hence:

-240º + 360º = 120º.

Then we have to find the equivalent on the first quadrant. 120º is on the second quadrant, hence:

180º - 120º = 60º.

The reference angle of the angle of -240º is of 60º.

On the second quadrant, the sine is positive, hence:

[tex]\sin{-240^\circ} = \sin{60^\circ} = \frac{\sqrt{3}}{2}[/tex]

More can be learned about reference angles at https://brainly.com/question/16884420

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