Oh, that's an excellent question! I do not know...let me see if I can find out

According to what I have read the scale IS 54mm, which doesn't mean much I suppose.
Each Miniature represents one creature, so a standard fight is between two teams of 6 people each (represented by 6 minis) so my guess is each Inch would be, say 10 feet.

Sadly, I don't think they ever took proper scale into account, hence the reason the game failed, the scale turned off a lot of people (as well as the price)

My son is a mere 8 years old, so we're not too hardcore about correctness of things like this. Range for attacking is measured in hexes as opposed to feet, so my opinion would be to use your best judgement

However, I may have been mistaken about the size of the hexes, I think it's more like 2" side to side, but will know more when I get home and properly measure (I was going from memory)