Which lines measure east-west position relative to the prime meridian?

• A. Longitude lines
• B. Latitude lines
• C. Equator lines
• D. Meridian lines

Answer: (A)

Longitude lines measure east-west position relative to the prime meridian. They stretch from the North Pole to the South Pole and are defined by their angle east or west of the prime meridian, which is 0 degrees at Greenwich. As you move east or west, your longitude increases toward 180 degrees. Latitude lines, by contrast, measure how far north or south you are from the equator, which is 0 degrees latitude. The term meridian is another name sometimes used for these lines, but the standard term for the east-west measurement is longitude lines.