The equator, which is numbered 0°, circles the Earth. That circle - the equator - is approximately 25,000 miles around. As in any circle, the equator included, there are 360 units of measurement called degrees. Each degree of longitude that crosses the equator is approximately 70 miles east-west. You can see that a degree has been set off on the diagram below.


Practice in computing distances on the equator

  1. What is the distance in miles on the equator from 0° longitude to 30°W? Answer: 30°x70 miles = 2,100 miles.
  2. How many miles on the equator is it from:
    1. 15°W - 45°W? ________________
    2. 20°W - 30°W? ________________
    3. 30°E - 60°E? _________________
    4. 15°W - 15°E? _________________
    5. 30°E - 15°W? _________________
    6. 5°W - 15°E? __________________