How much major lines of latitude are there?

Answer 1

The "lines of latitude" are a system of measurement; they don't actually have a physical existence in the real world. So the answer is either "none" or "an infinite number".

"MAJOR latitude lines" would depend on the scale of your map; generally either 15 degrees per line or 10 degrees per line.

We measure latitude in degrees north or south of the equator; the north pole is 90N, and the south pole is 90S. So there are 90 degrees north or south - but each degree is subdivided into 60 minutes, and each minute is subdivided in to 60 seconds, and you can use decimals to subdivide the seconds. Each minute of latitude works out to one nautical mile on the ground, so each second of latitude is about equal to 34 yards.

There are five latitude lines that actually have some physical significance. First is the equator, at zero. Then the Tropic of Cancer at 23 degrees 26 minutes north, and the Tropic of Capricorn at 23 26S. Finally, the Arctic Circle and Antarctic Circle at 66 degrees 34 minutes north and south respectively.