Angular distance from radius of sphere and distance along circumference

anglecirclesgeometry

How can I calculate the angular distance between 2 points on the circumference of a circle with only the distance along the circumference between the 2 points and the radius of the circle? I spent some time looking for the answer on how to do this but haven't found anything yet.

Best Answer

Basic idea: You know how far you have to go if you have to go around the whole circle (that's the circumference). That corresponds to $360^\circ$. Now consider how much of the circumference you're using. That corresponds to whatever the angle is.