using System;

using System.Text.Json;

​

public class Triangle

{

    public double A { get; set; }

    public double B { get; set; }

    public double C { get; set; }

    public double GetArea ()

    {

        double p = (A+B+C)/2;

        return System.Math.Sqrt(p * (p - A) * (p - B) * (p - C));

    } 

}

​

public class Program

{

    public static void Main()

    {

        Triangle triangle = new Triangle();

        triangle.A = 9.52;

        triangle.B = 5.01;

        triangle.C = 5;

        string t = JsonSerializer.Serialize<Triangle>(triangle);

        Console.WriteLine(t);

        Console.WriteLine(triangle.GetArea());

    }

}