# Longitude and Latitude

Welcome to class!

In today’s class, we will be talking about longitude and latitude. Enjoy the class!

### Longitude and Latitude

• #### Longitude:

1. A meridian is a great circle.
2. Half a meridian is called longitude.
3. Greenwich / prone meridian (Longitude 0°) is a reference meridian.
4. Other longitudes are measured to the west or east of the Greenwich meridian i.e. 0° – 180° W or 0° – 180° E.
• #### Latitude:

1. The equator is a great circle.
2. The other smaller circles are called parallels of latitude.
3. The equator is the reference latitude.
4. Other latitudes are measured to the north or south of the equator i.e. 0° – 90° N or 0° – 90°S.
##### Great Circles:

A great circle is a circle whose centre is also the centre of the earth. The equator and the meridians are all great circles.

##### Length of Parallel of Latitude:

The radius is given by r = R cos a

where a is the angular difference.

R is the radius of the earth.

In our next class, we will be talking more about Longitude and Latitude. We hope you enjoyed the class.

Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.

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