Longitude lines are associated with which reference point?

Longitude lines are associated with the prime meridian, which is the reference point for measuring degrees of longitude. The prime meridian is defined as 0 degrees longitude and runs from the North Pole to the South Pole, passing through Greenwich, England.

Longitude lines, which are also known as meridians, are vertical lines that run north-south and measure the distance east or west of the prime meridian. These lines help in pinpointing geographical locations on Earth's surface.

In contrast, the equator is the reference point for latitude, representing 0 degrees latitude and dividing the planet into the Northern and Southern Hemispheres. The Tropic of Cancer and the International Date Line also serve specific roles; however, they do not serve as the primary reference point for measuring longitude. The Tropic of Cancer is related to solar positions and seasonal changes, while the International Date Line mainly serves as a demarcation for calendar days and timekeeping.