Final answer:
A line connecting all points along the same longitudinal angle is called a meridian, which determines the longitude of any location on Earth.
Step-by-step explanation:
A line that connects all points along the same longitudinal angle is called a meridian. Meridians are great circles that pass through the North and South Poles and are perpendicular to the equator. This system is used to specify the east-west location, or longitude, of any place on Earth. The meridian that passes through Greenwich, England is known as the Prime Meridian, and it serves as the zero degree longitude from which all other longitudes are measured.