Calculate distance between two points

PointDistanceExtension.cs

public static class PointExtensions
{
  public static double DistanceFrom(this Point point1, Point point2)
  {
    // Pythagorean distance calculation.
    return Math.Abs(
            Math.Sqrt(
              Math.Pow(point1.X - point2.X, 2) + Math.Pow(point1.Y - point2.Y, 2)
              )
            );
  }
}