The equator is 25,000 miles long. However, not all lines of latitude are the same distance around the Earth. This is because the lines of latitude get shorter and shorter as they approach the North and South Poles. For example, the 30°N line and the 30°S line are about 21,600 miles long. If we divide 21,600 by 360°, we find that one degree equals 60 miles. The diagram below shows the number of miles in one degree of longitude on certain lines of latitude.

- How many miles is it from A to B? Answer: A degree on the 40°N line of latitude is 53 miles. There are 75° between A and B, so, 75°x 53 miles = 3,975 miles.
- How many miles is it from:
- C to D? _____________________
- K to L? _____________________
- F to G? _____________________
- M to K? _____________________

## Finding distances on lines of longitude

Just as the equator is about 25,000 miles around, so are all the lines of longitude. Therefore, every degree of latitude on a line of longitude is about 70 miles.

On the map above there are 10° of latitude between G and H. To find the distance in miles between these two places simply multiply 10° x 70 miles, or 700 miles. Complete the table below so that it will show the distances between places on the diagram.

Places Number of Line of Longitude Distance in Miles F to L | | A to K | | G to H | | E to M | | B to N | |