The meridian exactly halfway around the world from the prime meridian is called the 180th meridian or the antimeridian. This line represents the opposite side of the Earth from the prime meridian and is where the International Date Line is located.
Assuming that "all the way west of the Prime Meridian" would be on the opposite side of the globe from the prime meridian, or at 180o, "halfway west of the Prime Meridian" would be the 90oW meridian.
The major line of longitude located at 180 degrees longitude is the International Date Line.
The prime meridian is located at 0 degrees longitude.
The halfway point between the Prime Meridian (0°) and the 180° line of longitude is the 90° line of longitude, also known as the International Date Line. This line is located in the Pacific Ocean and marks where each new day begins.
prime meridian!Prime Meridian!PRIME MERIDIAN!PrImE MeRiDiAn!
The imaginary line at zero degrees longitude is the Prime Meridian. The imaginary line halfway between the poles is the Equator. The Equator is zero degrees latitude.
The Prime Meridian
The Prime Meridian
This is called the Prime meridian, it passes through Greenwich, England.
The Prime Meridian, located at 0 degrees longitude, marks the starting point for measuring longitudes.
The prime meridian in located at 0 degress longitude, and passes through Grenich, England.