Without using a calculator compute the sine cosine and tange

Without using a calculator, compute the sine, cosine, and tangent of 120 degree by using the reference angle. (Type squareroot (2) for squareroot 2 and squareroot (3) for squareroot 3.) What is the reference angle? degrees. In what quadrant is this angle? (answer 1, 2, 3, or 4) sin(120 degree) = cos(120 degree) = tan(120 degree) =

Solution

Reference angle positive, to the x-axis.
So Reference angle of 120 is, 180120=60
and 120 lies in the Second Quadrant.

sin 120 = sin 60 = sqrt(3)/2

cos 120 = -cos 60 = -0.5

tan 120 = -tan 60 = -sqrt (3)