Introduction to Trigonometry?

Question

If a nautical mile is the arc length intercepted on the surface of the earth by a central angle of measure one minute, fine the number of feet in one nautical mile. ( Assume that the redius of the earth is 2.09 x 10^7 feet.)

Answer 1

arc length = rx where r is radius and x is angle
arc length = 2.09 *10^7 * pi/(60*180) =6,060 feet