Zoom to Scale

[DawnBlanchard]

I know this question has been asked a couple of times but I haven't been able to find the Map Unit In Feet instead of Degrees or Meters.  This is the code that I am using but need to fill in the Map Unit:
           
double dpi = 96; //Set to resolution of your screen
string Scale = MapScale.Text;
double scale = double.Parse(Scale);
double mapunitInMeters = 111319.5; //size of one degree at Equator. Change if you are using a projection with a different unit than degrees
double newRes = scale / (dpi * 39.37 * mapunitInMeters);
Map.ZoomToResolution(newRes);

Does anyone know what the Map Unit In Feet is?  Also does the 39.37 number need to change for NAD 83 Feet projection?

Thanks in advance!

[RobertBurke]

There was a similar discussion about this same topic:
http://forums.esri.com/Thread.asp?c=213&f=2455&t=285205

Also the 39.37 represents the number of Inches in 1 meter.

DPI * 39.37 would result in the number of dots per meter.