private void button1_Click(object sender, EventArgs e) { if (firstbutton.Checked == true) { this.Hide(); ChangeASide form = new ChangeASide(A); form.Show(); } if (secondbutton.Checked == true) { MessageBox.Show("Perimeter = " + A.Perimeter()); } else if (thirdbutton.Checked == true) { string ab = A.AngleAB().ToString(); string bc = A.AngleBC().ToString(); string ac = A.AngleAC().ToString(); MessageBox.Show(" 1 - " + ab + "\n" + " 2 - " + bc + "\n" + " 3 - " + ac); } else if (fourthbutton.Checked == true) { if (A.IsEquality()) { double Side = A.GetFirstSide(); MessageBox.Show("Area = " + (Side * Side * Math.Sqrt(3)) / 4); } else { MessageBox.Show("ERROR! The triangle is not equlibrium! Try again."); } } else if (fourthbutton.Checked == false && secondbutton.Checked == false && thirdbutton.Checked == false && firstbutton.Checked == false) { MessageBox.Show("Choose the option PLEASE"); } }