Concersion angle degré/minute

Bonjour,
Voici l'exemple de ce que je souhaite faire:
conversion de 10,30 (soit un angle de 10°30) devient 10,50 (simple régle de 3 sur la partie décimale soit ici 0.30*100/60).
J'ai trouvé le module ci dessous sur le forum microsoft mais il m'oblige à taper '10°30'00 et ne se met pas à jour quand je change les valeurs?.
Etant une "bille en Vba, merci à ceux qui pourront m'aider...
Function Convert_Decimal(Degree_Deg As String) As Double
' Declare the variables to be double precision floating-point.
Dim degrees As Double
Dim minutes As Double
Dim seconds As Double
' Set degree to value before "°" of Argument Passed.
degrees = Val(Left(Degree_Deg, InStr(1, Degree_Deg, "°") - 1))
' Set minutes to the value between the "°" and the "'"
' of the text string for the variable Degree_Deg divided by
' 60. The Val function converts the text string to a number.
minutes = Val(Mid(Degree_Deg, InStr(1, Degree_Deg, "°") + 2, _
InStr(1, Degree_Deg, "'") - InStr(1, Degree_Deg, _
"°") - 2)) / 60
' Set seconds to the number to the right of "'" that is
' converted to a value and then divided by 3600.
seconds = Val(Mid(Degree_Deg, InStr(1, Degree_Deg, "'") + _
2, Len(Degree_Deg) - InStr(1, Degree_Deg, "'") - 2)) _
/ 3600
Convert_Decimal = degrees + minutes + seconds
End Function