wildfire3 Drawing Setup option documentation for: view_scale_format            

view_scale_format

formats the view scale ratio.  

• decimal*—expresses the view scale as decimals.

• fractional—expresses the view scale as fractions.

• ratio_colon—displays the view scale values as a ratio. for example, instead of a view scale of 0.5, displays the view scale as 1:2. since the ratio is just another way of displaying a fraction, make sure that you set the view_scale_denominator drawing setup option appropriately.