Calculate the distance between the equator (latitude 0) and a city Z in Egypt (latitude 30N).

Step 1: Analyze the question You need the distance along a meridian (north-south) between latitude 0° and latitude 30°N. That is an arc of 30° of latitude.

Step 2: The concept One degree of latitude is about 111 km everywhere on Earth. This comes from the Earth's circumference (about 40,000 km) divided by 360°:

40,000 ÷ 360 ≈ 111.1 km per degree

So: Distance = difference in latitude × 111 km

Step 3: Solution Difference in latitude = 30° − 0° = 30°

Distance = 30 × 111.1 km ≈ 3,333 km

Using 111 km per degree gives 30 × 111 = 3,330 km.

Step 4: Answer The closest option is **C.

Check on the other options:

• A (2,300 km) would be about 20.7°.
• B (3,000 km) would be about 27°, which would work if you wrongly used 100 km per degree.
• D (4,430 km) would be about 40°.

Exam tip: Remember "1° of latitude ≈ 111 km". For any north-south distance question, subtract the latitudes if the points are on the same side of the equator, or add them if on opposite sides, then multiply by 111. The same shortcut works for any city and any latitude difference. For east-west distances along a parallel, you would also multiply by cos(latitude).