I've been trying to figure this out for several hours now and am having trouble finding the right solution.
Given two points on a circle and the radius of the circle I need to calculate the distance in degrees between the two points on the circle. Here's a picture of what I'm trying to do.
In this picture I have a point at (-12.2,12.7) which represents the center of the circle. I know the radius of the circle (5.344) and I have two points on the circle. One at (-12.4,7.4) and another at (-17, 13.7). I need to get the length of the arc in degrees. I know if I have the center angle I can calculate the arc length, but I can't find anything about how to determine the center angle without already knowing the arc length.
Any help much appreciated.
Updating the image to use real values