Where is the International Date Line located?

The International Date Line is primarily located along the 180 degrees longitude meridian, which is directly opposite the Prime Meridian (0 degrees longitude). This line serves as the demarcation point for calendar days, where the date changes when crossed.

While the concept of longitude encompasses all lines running from the North to South Pole, the Date Line is specifically established to accommodate the Earth's rotation and the needs of global time zones. Its primary purpose is to ensure that the people living on either side of the line maintain a consistent understanding of the date, despite variations in local time.

The other choices inaccurately describe the line's location. The equator is a line of latitude, not relevant to the recent discussion of the Date Line. Similarly, 90 degrees west longitude and the Tropic of Cancer pertain to other geographical markers but do not define the International Date Line's position. Thus, understanding that it lies at 180 degrees longitude emphasizes its role in connecting global timekeeping and the Prime Meridian.