Compute angle between 3 points

angleBetweenPoints

protected static function angleBetweenPoints (p0:Point, p1:Point, p2:Point):Number
{
	var a:Number = Math.pow(p1.x - p0.x, 2) + Math.pow(p1.y - p0.y, 2);
	var b:Number = Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2);
	var c:Number = Math.pow(p2.x - p0.x, 2) + Math.pow(p2.y - p0.y, 2);
	return Math.acos((a + b - c) / Math.sqrt(4 * a * b));
}