title: How to find points on the circumference of a arc knowing a start point, an end point and the radius?
body: <p>Please see the image below for a visual clue to my problem:</p>
  
  <p><img src="https://i.stack.imgur.com/GT3ai.png" alt="Problem"></p>
  
  <p>I have the coordinates for points 1 and 2. They were derived by a formula that uses the other information available (see question: <a href="https://stackoverflow.com/questions/14359823/how-to-calculate-a-point-on-a-circle-knowing-the-radius-and-center-point">How to calculate a point on a circle knowing the radius and center point</a>).</p>
  
  <p>What I need to do now (separately from the track construction) is plot the points in green between point 1 and 2.</p>
  
  <p>What is the best way of doing so? My Maths skills are not the best I have to admit and I'm sure there's a really simple formula I just can't work out (from my research) which to use or how to implement.</p>