1. Determine 2 positive and 2 negative principal angles for a terminal arm with a related acute angle of 20 in quadrant III. 2. Using the CAST rule, state the sign of each of the following: sin 220 cos 320 tan 112 3. Determine sin 0 to 3 decimal places if cos 0 = 1/2 and 0 is an angle in quadrant IV. 4. The CAST Rule describes for a quadrant which ratios have positive values. Describe why the tangent ratio is positive only in quadrants I and III. 5. Given a point on the x-y plane, explain how you would determine a principal angle that would correspond to a terminal arm containing that point.