Question

Two islands are in the ocean. If the central angle with vertex at the center of the earth and rays that pass through these two islands measures 12’, how many statute miles apart are they?

Answer 1

The central angle with vertex at the center of the Earth is : α = 12` = 1/5° = 0.2°.
The distance between two islands:
L = R π α / 180°
Earth radius = 6,317 km = 3,959 miles
L = 3,959 · 3.14 · 0.2° / 180°
L = 13.82 miles
Answer: Two islands are 13.82 statute miles apart.