Calculation of Volume Surface Area and Diagonal of Cuboid

Public Class Form1
    Dim l, b, h, vol, sa, diag As Single
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        l = TextBox1.Text
        b = TextBox2.Text
        h = TextBox3.Text
        vol = l * b * h
        sa = 2 * ((l * b) + (b * h) + (h * l))
        diag = (l ^ 2 + b ^ 2 + h ^ 2) ^ (1 / 2)
        TextBox4.Text = vol
        TextBox5.Text = sa
        TextBox6.Text = diag

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub
End Class