If you use a ListBox content control titled 'Size' then the following macro in the ThisDocument module of the document/template will populate the two text controls with the values shown, when you click out of the list box.
Code:
Private Sub Document_ContentControlOnExit(ByVal ContentControl As ContentControl, Cancel As Boolean)
Dim oCC As ContentControl
If ContentControl.Title = "Size" Then
If ContentControl.ShowingPlaceholderText = False Then
Select Case ContentControl.Range.Text
Case "Large"
Set oCC = ActiveDocument.SelectContentControlsByTitle("Height").Item(1)
oCC.Range.Text = "123 cm"
Set oCC = ActiveDocument.SelectContentControlsByTitle("Width").Item(1)
oCC.Range.Text = "234 cm"
Case "Small"
Set oCC = ActiveDocument.SelectContentControlsByTitle("Height").Item(1)
oCC.Range.Text = "25 cm"
Set oCC = ActiveDocument.SelectContentControlsByTitle("Width").Item(1)
oCC.Range.Text = "36 cm"
End Select
Else
Set oCC = ActiveDocument.SelectContentControlsByTitle("Height").Item(1)
oCC.Range.Text = ""
Set oCC = ActiveDocument.SelectContentControlsByTitle("Width").Item(1)
oCC.Range.Text = ""
End If
End If
Set oCC = Nothing
End Sub
Had there been more than two values to consider, you could have added values to the list box and split the values to provide the results.
You may find
Insert Content Control Add-In useful.