How to determine distance using a degree grid?

1.To measure the distance along the equator, you need to determine the longitudes of the points, and calculate the difference in degrees. Length of 1 degree at the equator = 111.3 km. Multiply the difference in longitude by the value in kilometers of one degree.
2. To measure the distance along the parallels, you need to multiply the difference in longitudes by the value in km on a given parallel, using the atlas data
3. To measure the distance at any meridian, you need to determine the difference in latitudes in degrees and multiply by 111.3 km.
4. When measuring north and south latitude or west and east longitude, not the difference is determined, but the sum of latitudes or longitudes.