Question

How many great circles are there on earth?

Answer 1

Equator along with the lines of longitude are great circles and also all the lines of latitude(excluding equator) and two poles are small circles on earth.
Except them there are many more small circles and great circles...

I hope it will help you....

Answer 2

Answer:

Great circles are those circles that divide the earth equally into two parts. A great circle is the largest circle that can be drawn on any given sphere. There are 361 degrees of great circles on our home planet, earth.

Explanation:

Latitude - The 0-degree latitude, equator, is the only latitude great circle there is. This is because the latitudes run in an east-west direction and the Arctic circle, Tropic of Capricorn, or any other latitude (which is besides the equator of course) does not divide the earth equally into two. However, the equator does. Thus, the equator is the only latitude great circle.

Longitude - All longitudes are great circles. This is because they run in a north-south direction and the Prime meridian (Greenwich meridian) and the International Date Line (IDL) together form a great circle. This is because they divide the earth equally into two. Thus, all longitudes are great circles.