title: how to find overlapping of circle
body: <p>Hi there I made an application which has two balls.Red and Yellow.
  User has to drag <code>RED BALL</code> and drop it over the <code>YELLOW BALL</code>.it is in X-Y Plane.now i want to calculate what is the accuracy is the overlapping. I know that if the X-Y of target are equal to the X-Y of the Striker then it is 100 percent but how will you calculate it? as if you move the red ball further right value of X of striker gets bigger and percent will not be accurate?I have been using Percent Error formula but it is not accurate</p>
  
  <pre><code>   double percentErrorX =(CurrentX-targetX)*100/targetX;
              double percentErrorY = (CurrentY -targetY)*100/targetY;
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/tsUG1.jpg" alt="enter image description here"> </p>