How can you used longitudes to calculate time?

Longitudes can be used to calculate time by recognizing that the Earth is divided into 360 degrees of longitude, and it rotates 360 degrees in approximately 24 hours. This means that each degree of longitude corresponds to about 4 minutes of time (60 minutes/360 degrees). By knowing the longitude of a location, you can determine its standard time relative to Greenwich Mean Time (GMT), which is based on the prime meridian at 0 degrees longitude. For example, if a location is 15 degrees east of GMT, it is 1 hour ahead of GMT.