Chapter 5

Converting minutes and decimal form

Minutes to decimal form = Divide by 60.
Decimal form to minutes = Multiply by 60.

Arc length formula (s)

s = πrθ / 180, where θ is the angle in degrees.

Shortest distance between two points on Earth

The distance along the great circle that passes through those two points.

Meridians of longitude

Semi-great circles that pass through the north and south poles.

Parallels of latitude

Small circles whose planes are parallel to that of the equator.

Angular distance (same meridian, same hemisphere)

Subtract the smaller latitude of the two locations from the larger.

Angular distance (same meridian, different hemispheres)

Add the two latitudes together.

Angular distance (same parallel of latitude)

Found by either adding or subtracting the longitudes.

Longitude and time (hours)

15° of longitude equals a 1 hour time difference.
1° of longitude equals a 4 minutes time difference.

UTC

The primary time standard serving as the basis for all other time zones. Locations to the East are ahead of UTC; locations to the West are behind UTC