Question

Find the exact ratios for sine, cosine and tangent of 255°

Answer 1

one way i can think of is to first find it for
510 degrees, thats same as 150 degrees

then if you know double angle formula, getting ratios of 255 from 510 would not be difficult

Answer 2

You can just put it in your calculator, then square it, and it'll give you exact, just remember to put a sqrt root sign back on it