Examples of Great circles and Meridians?

Question

Hi everyone, I need 2 examples of great circles and 4 examples of meridians. I've searched thoroughly but only found some. This is for year 11 Maths A, navigation. If you can help it would be greatly appreciated.

Answer 1

Meridians are lines of longitude that form great circles all of which meet at the north and south poles.   The most well known meridians are the prime meridian (0 degrees longitude passing through Greenwich, England), and the international dateline (passing through 180 degrees longitude).  All the other meridians are known simply by their number of degrees east or west of the prime meridian until they meet at the dateline.   So two other meridians might be  30 degrees west and 70 degrees east.

Great circles are basically routes that circle the earth using the longest possible direct route.   Examples of Great circles are:

1. The Equator

2. Prime Meridian

3. International Date Line (180 degrees meridian)

4. London to Auckland (New Zealand) and back again circling the globe on the opposite side to the one you started on.  Auckland is the antipodal point on the other side of the globe to London.

Great circles differ from meridians in that meridians must pass through the poles.   Great circles can be on any point on the globe so long as they take the longest direct route possible without backtracking.    The equator is a great circle.  The Arctic circle and the tropic of Cancer are not.

Answer 2

A meridian is a special case of a great circle that passes through the poles. The Greenwich meridian taken together with the 180 degree meridian is one example.

The equator is a great circle but not a meridian.