title: Calculate angle of touched point and rotate it on a fixed image or canvas or bitmap image in Android
body: <p>Ohh.. damm Math !! once again stuck. It seems to be easy but i think its not that easy, 
  Problem Statement: I want to rotate the 3 fixed points which lies on a fixed circle.
  1.when 1 point is selected remaining 2 points should be static mode and only selected point should move/rotate on circumference of circle.
  2.And all 3 points are connected via 3 lines as shown in images..when we select a point and rotate it,connected lines also increase and decrease..</p>
  
  <p>I already tried to solve this problem finding angle at each instant after touch.but its not quite working as per my need..</p>
  
  <p>something like this <img src="https://i.stack.imgur.com/SNAyW.png" alt="enter image description here"> </p>
  
  <p><img src="https://i.stack.imgur.com/RaKcn.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/RaKcn.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/7YpF4.png" alt="enter image description here"></p>