4.1 visual triangulo

namespace practica4._1form
{
public partial class TrianguloF : Form
{
public TrianguloF()
{
InitializeComponent();
}

private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{

}

private void button1_Click(object sender, EventArgs e)
{
double Lado1, Lado2, Lado3, Area, Perimetro, SP;

Lado1 = double.Parse(textBox1.Text);
Lado2 = double.Parse(textBox2.Text);
Lado3 = double.Parse(textBox3.Text);
Perimetro = Lado1 + Lado2 + Lado3;
SP = Perimetro / 2;
Area = Math.Sqrt((SP - Lado1) * (SP - Lado2) * (SP - Lado3) * SP);


listBox1.Items.Add("El Area es: " + Area);
listBox1.Items.Add("");
listBox1.Items.Add("El Perimetro es: " + Perimetro);
}

private void button2_Click(object sender, EventArgs e)
{
textBox1.Clear();
textBox2.Clear();
textBox3.Clear();
listBox1.Items.Clear();
}

private void button3_Click(object sender, EventArgs e)
{
Close();
}


}
}