Public Function GetScale( _
   ByVal extent As Envelope, _
   ByVal mapWidth As Integer, _
   ByVal mapHeight As Integer _
) As Double

Dim instance As MapFunctionality
Dim extent As Envelope
Dim mapWidth As Integer
Dim mapHeight As Integer
Dim value As Double
 
value = instance.GetScale(extent, mapWidth, mapHeight)

public double GetScale( 
   Envelope extent,
   int mapWidth,
   int mapHeight
)