Explanation:

The longitude of a place is the angular distance of that place east or west of the Prime Meridian. It is measured along the parallel that passes through the place. Like latitude, it is also measured in degrees, minutes and seconds. All longitudes to the cast of the Prime Meridian are denoted by the letter E, while longitudes to the west of the Prime Meridian are denoted by the letter W. Let us take an example. Find out Jabalpur in India and Pittsburgh in U.S.A. You will notice that both lie on 80 ° longitude. However, Jabalpur is located east of the Prime Meridian. So, its longitude is 80 ° E. On the other hand, Pittsburgh is located to the west of the Prime Meridian. So, its longitude is 80 ° W.