code: function(p1, p2) {
      var r = {
          c: 90,
          A: Math.abs(p2.x - p1.x),
          B: Math.abs(p2.y - p1.y)
      };
      var brad = Math.atan2(r.B, r.A);
      r.b = this.toDegrees(brad);
      // r.C = Math.sqrt(Math.pow(r.B, 2) + Math.pow(r.A, 2));
      r.C = r.B / Math.sin(brad);
      r.a = 90 - r.b;
  
      return r;
  }
docs: Solve a 90 degree triangle from two points.
  @param  {Number} p1.x Point 1 x coordinate
  @param  {Number} p1.y Point 1 y coordinate
  @param  {Number} p2.x Point 2 x coordinate
  @param  {Number} p2.y Point 2 y coordinate
  @return {Object}    A triangle object {A,B,C,a,b,c}