Given the image below, A is the centre of the circle, B is a point on the circumference and AC and DB lie on parallel lines.
Knowing A, C, D and the radius of the circumference, I need to find the quickest way (in term of # of calculations) to find B.
The position of C can vary, AC can also be parallel to x or y axis. This is for a program I'm making, I need to handle also corner cases in terms of calculations where the slope can be infinity (computers don't work well with infinity). In this context I found that using trigonometric functions I can achieve better results, but in this particular case I've come to no good solutions.