Vertices (15,0) and (-15,0), conjugate axis of length 4 units

When you are making a circle graph by hand, how do you convert a number for a part into its corresponding angle measure in the circle graph? when you are making a circle graph by hand, what should you do if one of your angle measures is greater than 180°?

Thee blue triangle has rotated from quadrant i to quadrant iii about the origin. describe the effects of the rotation on the coordinates of the blue triangle.

How can you tell when x and y are not directly proportional?