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**tinu** The question asks to find the sine of 5pi/7. My teacher says to add/subtract an n value of pi to get a value on the unit circle; and then I find the sine. I've been at this problem for awhile and there has to be a better way than guessing how many pi's it will take to get a value on the circle.

What is the answer?

I tried to add 2 pi.

5pi/7 + 14pi/7 = 19pi/7 (Not on the unit circle!)

Then 4 pi.

5pi/7 + 28pi/7 = 33pi/7

The idea is that its supposed to reduce to a value on the unit circle. . . But I tried some other numbers, and I can't get it!