## Algebra and Trigonometry 10th Edition

$sin~120°=\frac{\sqrt 3}{2}$ $cos~120°=-\frac{1}{2}$ $tan~120°=-\sqrt 3$
Let $θ'$ be the reference angle. We must have that $0°\leqθ'\lt360°$ But, since $0°\leqθ=120°\lt360°$, it is not necessary to find the reference angle. $sin~120°=\frac{\sqrt 3}{2}$ $cos~120°=-\frac{1}{2}$ $tan~120°=-\sqrt 3$