Convert measurement in Miles, Yards, Feet and Inches to a metric measurement in kilometers, meters and centimeters in VB.NET

DESCRIPTION:
Total inches = 63360*miles + 36*yards + 12*feets + inches
Meters = total inches / 39.37
PROPERTIES:

Button1
Text	Calculate
Button1
Text
ComboBox1
Items	Kilometer
	Meter
	Centimeter

CODEING:

Public Class Form1
    Dim total_meter As Double
    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
        If ComboBox1.Text = "Kilometer" Then
            Label5.Text = (total_meter / 39.37) / 1000
        ElseIf ComboBox1.Text = "Meter" Then
            Label5.Text = total_meter / 39.37
        ElseIf ComboBox1.Text = "Centimeter" Then
            Label5.Text = (total_meter / 39.37) * 100
        End If
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        total_meter = (63360 * Val(TextBox1.Text)) + (36 * Val(TextBox2.Text)) + (12 * Val(TextBox3.Text)) + Val(TextBox4.Text)
        Label6.Text = "Total Inches:" & total_meter
    End Sub
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        TextBox2.Text = Val(TextBox1.Text) * 1760
        TextBox3.Text = Val(TextBox1.Text) * 5280
        TextBox4.Text = Val(TextBox3.Text) * 12
    End Sub
End Clas

DESIGNING: