Question

at which longitude does the date change

Answer 1

The International Date Line around the antemeridian takes 180 degree longitude taken as an imaginary line of demarcation.

It lies on the surface of earth and runs from the North Pole and to the South Pole for demarcate the changes of one calendar day to the next.

This happens every day and date changes by means of International Date Line as an imaginary line of demarcation on the surface of earth.

Answer 2

I hope this helps you