using System; using System.Windows.Media.Media3D; class Program { static void Main(string[] args) { Point3D point1 = new Point3D(1, 2, 3); Point3D point2 = new Point3D(4, 5, 6); double distance = point1.DistanceTo(point2); Console.WriteLine($"The distance between point1 and point2 is: {distance}"); } }In this example, two points in a three-dimensional coordinate system are created using the Point3D constructor. The DistanceTo method is then called on the first point and passed the second point as an argument. Finally, the distance between the two points is printed to the console. The Point3D.DistanceTo method is part of the System.Windows.Media.Media3D namespace in the .NET Framework Class Library.