Which line serves as the primary reference for measuring longitude and runs through Greenwich?

Which line serves as the primary reference for measuring longitude and runs through Greenwich?

• A. Imaginary Date Line
• B. Prime Meridian
• C. Tropic of Cancer
• D. Equator

Answer: (B)

Longitude is measured from a starting reference line at 0 degrees, which runs through Greenwich, England, at the Royal Observatory. This line is known as the Prime Meridian and it provides the global baseline for determining longitude east or west of Greenwich. The other lines described serve different purposes: the International Date Line marks the change of calendar day rather than a zero longitude, while the Tropic of Cancer and the Equator are lines of latitude, measuring distance north or south from the Equator, not longitude.

Longitude is measured from a starting reference line at 0 degrees, which runs through Greenwich, England, at the Royal Observatory. This line is known as the Prime Meridian and it provides the global baseline for determining longitude east or west of Greenwich. The other lines described serve different purposes: the International Date Line marks the change of calendar day rather than a zero longitude, while the Tropic of Cancer and the Equator are lines of latitude, measuring distance north or south from the Equator, not longitude.