About Draw An Arc

Question

Hi,

 

In my application I having three points. StartPoint, EndPoint and PivotPoint. So my concern is I want to draw an Arc between StartPoint and EndPoint considering PivotPoint is center of an Arc always.

 

   As I moving my PivotPoint my arc should change as assuming PivotPoint is at center of Arc.

 

   Thanks In Advanced. I much needed this. So please give me solution as early as possible.