C# da Metod ile Ortalama Hesaplama

c#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int a = Convert.ToInt32(textBox1.Text);
            int b = Convert.ToInt32(textBox2.Text);
            int c = Convert.ToInt32(textBox3.Text);
            double x = aritmetikortalama(a, b, c);
            double y = geometrikortalama(a, b, c);
            double z = harmonikortalama(a, b, c);
            int d = 0;
            if (checkBox1.Checked==true)
            {
                listBox1.Items.Add("aritmetikortalama" + x);
                d = d + 1;
            }
            if (checkBox2.Checked==true)
            {
                listBox1.Items.Add("geometrikortalama" + y);
                d = d + 1;
            }
            if (checkBox3.Checked==true)
            {
                listBox1.Items.Add("harmonikortalama" + z);
                d = d + 1;
            }
            listBox1.Items.Add(d);
        }
        double aritmetikortalama(int x1, int x2, int x3)
        {
            return (x1 + x2 + x3) / 3.0;
        }
        double geometrikortalama(int x1, int x2, int x3)
        {
            double go;
            int carpım;
            carpım = x1 * x2 * x3;
            go = Math.Pow(carpım, 1 / 3.0);
            return go;
        }
        double harmonikortalama(int x1, int x2, int x3)
        {
            return 3.0 / ((1.0 / x1) + (1.0 / x2) + (1.0 / x3));
        }

    }
}