Answer:
21.25 km
Step-by-step explanation:
Hello
The numerical scales (E), are also known as scale reasons, the relationship with the size of the map, or a part of it, with its actual size on the ground. Thus, an E of 1: 10,000 means that one unit on the map is equivalent to 10,000 units on the ground.
in the problem we have E=1:250000
which means that one centimeter on the map equals 250000 cm in ground
1 cm (map)⇒250000 cm (ground)
using a rule of three
1 cm (map)⇒250000 cm (ground)
8.5 cm (map) =x cm ( ground)

converting that distance to km

100 cm=1m
1000m=1 km
so

x=21.25 km
have a great day.