When calculating slope using $ ext{ft/mi}$, if you convert both rise (feet) and run (miles) to the same unit (e.g., feet), what is the resulting numerical value multiplied by 1000 used for?

Question

Accepted Answer

Per mille ($ ext{ extperthousand}$). If you convert the mixed units to a single unit (e. g. , feet/feet), the resulting ratio is then multiplied by 1000 to express it in per mille ($ ext{ extperthousand}$), which standardizes the run base to 1000.