SOLUTION: How do I use reference angles to find the exact value of sin 240 DEG? I need to know the steps and the answers. I can't find it in my reading or my notes.

Question 329736: How do I use reference angles to find the exact value of sin 240 DEG? I need to know the steps and the answers. I can't find it in my reading or my notes.
Answer by texttutoring(324) (Show Source): You can put this solution on YOUR website!
240 is 60 degrees more than 180 degrees.
On the grid with a unit circle, this would put it in the lower left quadrant.

The reference angle would be 60 degrees. You always start at 0 degrees and move around in a counter-clockwise direction.

Knowing that the reference angle is 60 degrees, you can then draw a triangle, which will be a special triangle of 30-60-90, which you should know the ratios for.
The sin of 60 is sqrt(3)/2, so the sine of 240 will be -sqrt(3)/2.

Recall the principle of CAST (which specifies which quadrants have positive trig values).

Hope this makes some sense. It would be easier if I could draw a picture. If you need some clarifications, just let me know.
RELATED QUESTIONS
Use reference angles to find the exact value of the expression, sin... (answered by stanbon)

Use reference angles to find the exact value of the expression. Do not use a calculator: (answered by josmiceli,rothauserc)

How do I find reference angles? How do I know which quadrant certain angles are in such... (answered by stanbon)

hi, i need to know how i can find an exact value of Sin... (answered by chosenpoint,stanbon)

A and B are acute angles. Cos A equals 24/25 and Tan B equals 15/8. Find the exact value... (answered by greenestamps)

Use the characteristics of f(t) = sin t to find the value of sin t when t=-21π/4 I... (answered by MathLover1,MathTherapy,ikleyn)

use the reference angle to find the exact value of the given expression... (answered by lwsshak3)

use the reference angles to find the exact value of the expression: csc 4pi over... (answered by funmath)

use the reference angles to find the exact value of the expression: tan... (answered by venugopalramana)