myRadians = Math.atan2(_parent._y-_root._ymouse-this._y,_parent._x- _root._xmouse-this._x);
    myDegrees = Math.round((myRadians*180/Math.PI));
    this._rotation = myDegrees;


///in as3 its something like this
Math.abs(Math.atan2((y1-y2),(x1-x2)))*(180/Math.PI)