Question

Which line of longitude is used to fix the world standard time?state it's value in degrees

Answer 1

The line of longitude used to fix the WORLD STANDARD TIME is GREENWICH MERIDIAN or PRIME MERIDIAN.

Its also known as the 0° LONGITUDE.
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Answer 2

Answer:

International Date Line is the line of longitude use to fix the 'world standard time'. Its value is 0°.

Explanation:

They are '360 degrees' of longitude -'180 degree of longitude' east of the Prime Meridian, and '180 degrees of longitude' west of the Prime Meridian.

The 180° east and 180° West longitude meet and form a single line on the 'opposite side' of the world called the 180° longitude or the 'International Date Line.'

Thus the longitude of a place tells you how much east or west of the 'Greenwich Meridian' the place is located.