private void button1_click() { const float pi=3. 141592654f; float alan,cevre; int r; r=Convert.ToInt32 (textbox1.text); alan=pi*r*r; cevre=2*pi*r; textbox2.text=alan.ToString (); textbox3.text=cevre.ToString (); } özgür yılmaz o26ur_18@hotmail.com