16. in geography, latitude gives the north-south position of a
point on earth's surface. latitude is an angle, ranging from
0° at the equator to 90°n at the north pole and 90's at the
south pole. the overland distance between points on
earth's surface is an arc. with the central angle measured
from earth's center. the formula of the length, l, of an arc
with central angle x° on a circle with radius r is:
l = 2tr. 360
suppose that two cities have the same longitude, which
gives the east-west position of a point on earth's surface.
one has latitude 19°n, and the other has latitude 26°s.
assume earth is a sphere with a radius of 6,380 km. find
the distance between the two cities to the nearest
kilometer