Answer:
There are 5280.10 feets in 1 mile.
Explanation:
Initial altitude of an airplane = 20,000 feet
Final altitude of an airplane = 10,000 feet
Drop in an altitude of an airplane = 20,000 feet - 10,000 feet = 10,000 feet
Drop in an altitude of an airplane read by radar traffic control is 1.8939 miles


1 mile = 5280.10 feets