Visual Basic 2010

Public Class Form1
    Dim diagonal_1, diagonal_2, Hasil As Double
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Menghitung luas belah ketupat'
        diagonal_1 = Val(TextBox1.Text)
        diagonal_2 = Val(TextBox2.Text)
        Hasil = 0.5 * diagonal_1 * diagonal_2
        TextBox3.Text = Hasil
    End Sub
End Class