Practice and Revision - International Date Line
Let us practise and revise what we learned about international date line. The International Date Line is an imaginary line where the calenda
Core concept
The International Date Line roughly follows the 180° longitude meridian, running through the Pacific Ocean, avoiding populated landmasses where possible.
How it works
Crossing the date line from west to east means subtracting a day, while crossing from east to west means adding a day.
Why it matters
The date line exists because Earth is divided into 24 time zones, and without it, there would be confusion about which day it is.
Key detail
The date line's path zigzags around certain countries and territories to keep them on a consistent, convenient date for practical reasons.
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Key diagram

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Quick notes
• International Date Line: near 180° longitude.
• Runs through Pacific Ocean.
• Avoids populated landmasses where possible.
• West to east crossing: subtract a day.
• East to west crossing: add a day.
• Exists due to Earth's 24 time zones.
• Prevents date confusion globally.
• Line zigzags for practical country convenience.