namespace WindowsFormsApplication20
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {
            double prin;
            prixee pr = new prixee(Convert.ToDouble(textBox1.Text), Convert.ToDouble(textBox2.Text));           
            prin = pr.answer();
            textBox3.Text = prin.ToString("#.00");
        }
    }

    class pizza
    {
        private double diameter;
        public double  prize;
        private double radius;
        private double squarelen;
       
        public pizza(double meter, double price)
        {
            diameter = meter;
            prize = price;
            radius = diameter / 2;
            squarelen = radius * radius;
        }

        public double getarea()
        {   
            return 3.14 * squarelen;
        }

    }

    class prixee : pizza
    {
        public prixee(double meter, double price) : base(meter,price) {}
        
        public double answer()
        {
           return  prize / getarea();
        }
        
    }
}