* 1 degree = 60 minutes (written as 60')

* 1 minute = 60 seconds (written as 60")

Therefore, a degree of longitude can be expressed in this way:

* Degrees - Minutes - Seconds

* For example: 45° 30' 15"

This system is analogous to how hours are divided into minutes and seconds. It's important to note that this is not the only way to express longitude. Decimal degrees are also commonly used, which express the longitude as a decimal number.

Here's how to convert between the two:

* Degrees-Minutes-Seconds to Decimal Degrees: Divide the minutes by 60 and the seconds by 3600, and add all three values. For example, 45° 30' 15" = 45 + (30/60) + (15/3600) = 45.50417°

* Decimal Degrees to Degrees-Minutes-Seconds: Separate the whole number for the degrees. Multiply the decimal portion by 60 to get the minutes, then multiply the decimal portion of the minutes by 60 to get the seconds.

Understanding these subdivisions is crucial for accurately representing geographic locations and performing calculations involving latitude and longitude.