This is based on the Unit Circle

Question

Without using a calculator, compute the sine, cosine, and tangent of  by using the reference angle.(Type sqrt(2) for  and sqrt(3) for .)What is the reference angle? Incorrect--- degrees.

 

Incorrect

  

Answer 1

If you sketch out where 210° is you will see that it is 30°down from 180° so we can say the reference angle is 30°:

For a 30° angle:

1. sin(30°) = 1/2 however, since the sine is like the "y-value" and the y-value is negative in quadrant 3 where 210° is, then sine(210°) = -1/2
2. cos(30°) = √3/2 however, since the cosine is like the "x-value" and the x-value is negative in quadrant 3 where 210° is, then cosine(210°) = -√3/2
3. tan(30°) = √3/3 and it stays positive in Q3 (since both "x" and "y" values are negative their ratio produces a positive.

Regarding your question "t=3 is found in quadrant 2, what is the reference angle?", I'm unsure what you mean.