Option Explicit

Sub jjjRowHeightFixedInCM()
    Dim rngSelected As Range: Set rngSelected = Selection
    Dim varHeight As Variant
    varHeight = [A1].Value
    If IsNumeric(varHeight) Then
        If varHeight > 0 Then
            rngSelected.EntireRow.RowHeight = Application.CentimetersToPoints(varHeight)
        End If
    End If
End Sub