Answer: 850 km
Explanation:
The scale 1 cm : 85 km becomes 10 cm : 850 km when we multiply both parts by 10. We do this so that the "1 cm" becomes "10 cm". At this point, we have our answer.
You could also solve it like so
(1 cm)/(85 km) = (10 cm)/(x km)
1/85 = 10/x
1*x = 85*10
x = 850
