Explain how latitude and longitude are used?
They are used to pinpoint any location on the Earth.
Lines of latitude run parallel to each other in an east/west direction, and are measure in degrees starting at 0 degrees at the Equator and ending at 90 degrees at either North or South Poles.
Longitude lines run north/south, converging at the poles. The zero degree Longitude runs through Greenwich England and is called the Prime Meridian. The lines are then measured in degrees moving east and west from 0 until you reach 180 degrees or the international date line.
One degree can be divided into 60 minute and one minute into 60 seconds. The distance from one minute of latitude to the next is 1 nautical mile. As longitude converge at the poles the distance between minutes of longitude varies dependent on how far north/south you are.
Using these, every point on the Earth can be described using one latitude and one longitude. And since modern GPS can measure down to decimals of seconds, you can use a point of latitude and longitude and pinpoint yourself to within a meter of your EXACT spot on the Earth.