using System;

​

public class Program

{

    public static void Main()

    {

        // First location

        var lat1 = ToRadians(33.21977738253630);

        var long1 = ToRadians(-97.16391049789760);

​

        // Second location

        var lat2 = ToRadians(33.18047049907190);

        var long2 = ToRadians(-97.09456482658380);

​

        // Rectangular to Polar coordinate conversion (Pythagorean simplified)

        var x = (long2 - long1) * Math.Cos((lat1 + lat2) / 2);

        var y = lat2 - lat1;

        var d = Math.Sqrt((x * x) + (y * y));

​

        // Earth Mean Radius

        short radiusInMiles = 3963;

        short radiusInKilometers = 6378;

​

        Console.WriteLine($"distance = {Math.Round(d * radiusInMiles, 2)} miles ({Math.Round(d * radiusInKilometers, 2)} km)");

        return;

    }

​

    private static double ToRadians(double degrees)

    {

        // Circle is 360 Degrees or 2π Radians

        return Math.PI * degrees / 180.0;

    }

}