1mm on the map = 62500mm in real life
so
175mm on the map = 62500mm * 175 in real life = 10937500mm
There are 1000mm in a metre so
10937500/1000 = 10937.5m
so X = 10937.5
alternatively
1mm on the map = 62500mm in real life = 62.5m
so
175mm on the map = 62.5m * 175 in real life = 10937.5mm
so X = 10937.5