Trigonometry
Determine the angle measure θ\thetaθ without using a calculator. Express the answer in degrees.
θ=cos−1(−32)\theta=\cos^{-1}\left(-\frac{\sqrt3}{2}\right)θ=cos−1(−23)
60∘60^{\circ}60∘
30∘30^{\circ}30∘
210∘210^{\circ}210∘
150∘150^{\circ}150∘