Answer:
ok first there is a problem here there are actually 5280 NOT 5380 feet in a mile. Is this a typo or are you to assume a different length of a mile?
I will stick with the real value of 5280...
5280 feet/ mile * 0.62137119 miles/ km = 3280 f/km
3280 f/km / 4000 feet = .82 km
Explanation: