What is longitude a measure of?

Longitude is indeed a measure of distance east and west of the prime meridian. The prime meridian is the designated zero degrees longitude line that runs from the North Pole to the South Pole, passing through Greenwich, England. Longitude is expressed in degrees, with the values ranging from 0 degrees at the prime meridian to 180 degrees both east and west. This system allows for the precise location of points on the Earth's surface in relation to the prime meridian. Understanding longitude is essential for navigation, mapping, and understanding global positioning.

The other choices do not accurately define longitude. The measurement of distance north and south of the equator pertains to latitude, not longitude. Height above sea level refers to elevation and is not related to either latitude or longitude. Lastly, land use relates to how land is utilized and does not measure geographical position in terms of distance from reference points like the prime meridian or the equator.