Find the exact value of trigonometric ratios

Examples
Lessons
  1. Find the exact value of all six trigonometric ratios, then make a conclusion
    which primary trigonometric ratios (sin θ,cosθ,tanθ \theta , cos \theta, tan \theta) are positive in each
    quadrant
    1. θ \theta=30°
    2. θ \theta =120°
    3. θ \theta =225°
    4. θ \theta=300°