Whether travelling to the West or to the East from the Prime Meridian (zero Longitude) the International Date Line is 180 degrees Longitude.
121 degrees east longitude
International Date Line
Las Vegas is approximately 116 degrees west of the International Date Line, which lies at 180 degrees longitude. Therefore, there are about 64 degrees of longitude separating Las Vegas from the International Date Line.
The international date line
The major line of longitude located at 180 degrees longitude is the International Date Line.
The international date line (or there abouts)
180 degrees
180 degrees
180 degrees of longitude.
The International Dateline approximately follows the meridian of 180° longitude.
No. 90 degrees longitude is not a major line of longitude. Only 0 and 180 degrees longitude, which are the Greenwich Meridian and the International Date Line respectively, are major lines of longitude.
180 degrees east/west longitude