private void btnDikdörtgenAlanHesapla_Click(object sender, EventArgs e)
        {
            Alan alanDikdörtgen = new Alan(Convert.ToInt32(txtUzunKenarAlan.Text),
                                           Convert.ToInt32(txtKisaKenarAlan.Text));
            int sonucAlan = alanDikdörtgen.DikdörtgenAlanHesapla();
            txtSonucAlan.Text = sonucAlan.ToString();

        }
        private void btnKareAlanHesapla_Click(object sender, EventArgs e)
        {
            Alan alanKare = new Alan(Convert.ToInt32(txtKareAlan.Text));
            int sonucAlan = alanKare.KareAlanHesapla();
            txtSonucAlan.Text = sonucAlan.ToString();


            
        }