title: Equation to find the degrees of rotation of a once horizontal line
body: <p>hey so I have a center of an object and i'm making a line with this center as the start of it, and the mouse position the end of it. </p>
  
  <p>How do I find how rotated the second point (?,?) is around the stationary first point (0,0) ?<br>
  <strong>Note:</strong> if the second point were (1, 0) it would be roated 0 degrees.</p>