cara membuat program luas dan keliling segitiga, persegi dan lingkaran dengan vb.net

Kali ini saya mau berbagi tentang membuat program luas dan keliling segitiga, persegi dan lingkaran dengan vb.net, langsung aja liat source code dan desain formnya, monggo....

source code :
Public Class Form1

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        alas.Clear()
        tinggi.Clear()
        luas.Clear()
        keliling.Clear()
    End Sub

    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
        jari2.Clear()
        luaslingkaran.Clear()
        kelilinglingkaran.Clear()
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        If ComboBox1.Text = "Persegi" Then
            luas.Text = Val(alas.Text) * Val(tinggi.Text)
        ElseIf ComboBox1.Text = "Segitiga" Then
            luas.Text = (Val(alas.Text) * Val(tinggi.Text)) / 2
        End If
        If ComboBox1.Text = "Persegi" Then
            keliling.Text = (Val(alas.Text) + Val(tinggi.Text)) * 2
        ElseIf ComboBox1.Text = "Segitiga" Then
            Dim c As Double
            c = ((Val(alas.Text) ^ 2) + (Val(tinggi.Text) ^ 2)) ^ 0.5
            keliling.Text = (Val(alas.Text) + Val(tinggi.Text) + c)
        End If
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        Dim p As Double = 3.14
        luaslingkaran.Text = p * (Val(jari2.Text) ^ 2)
        kelilinglingkaran.Text = 2 * 3.14 * jari2.Text
    End Sub

    Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
        Me.Close()
    End Sub

    Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click
        Me.Close()
    End Sub
End Class

Desain formnya :