Trigonometry: Angles

Quadrant III.

Quadrant IV

Two.

Basically one. Any plane with two perpendicular lines drawn in is a coordinate plane, with the origin at the intersection of the lines, or axes. So any plane can have axes drawn in and coordinates measured. If there were more than one coordinate plane, though (perhaps two parallel planes each have a pair of perpendicular axes drawn in them), then they would be exactly the same, anyway. So essentially there is only one coordinate plane.