Given a coordinate circle with points at (0,100), (100,0), (0,-100), and (-100,0), how does one find the coordinates of a point on the circle? Let's assume the point (A,B) is between (0,100) and (100,0) . The distance from (A,B) to (0,100) is also known. Thus, knowing the radius to be 100, it would seem we could find the angle formed by (0,100), (0,0) and (A,B). Now, how does he determine the coordinates of (A,B)?
BTW, he is doing this for a science project in astronomy. He is doing something involving two planets and an asteroid (detemining the effects of the planets on the orbit of the asteroid).
Any help (or pointers to sources) would be greatly appreciated.