I'm not understanding what your goal is. The following is my best guess of what you are wanting but some of it I've just made up because you haven't included much detail.
You have two balls that are on the screen. Ball A and Ball B. Both balls are in a fixed location on screen. Ball A is rotating and Ball B is stationary. When Ball A spawns on the screen at some random location, Ball B must be at least 100 pixels radius away from Ball A.
If this did not describe what you want, then describe in detail what you want just like I did.