find the area of a regular polygon inscribed in a circle in csharp

main.cs
using System;

namespace PolygonArea
{
    class Program
    {
        static void Main(string[] args)
        {
            // Inputs
            int n = 6;     // Number of sides
            double r = 5;  // Radius of circle

            // Calculate area
            double A = 0.5 * n * Math.Pow(r, 2) * Math.Sin(2 * Math.PI / n);

            // Output result
            Console.WriteLine("Area of the polygon: " + A);
        }
    }
}
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main.cs
Area of the polygon: 64.9519052838329
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