Question

how are the equator and the prime meridian used on maps?
to separate earths four hemispheres
to measure distances east and west
to identify the location of earths continents

Explanation:

The equator splits Earth into Northern and Southern Hemispheres, while the prime meridian splits it into Eastern and Western Hemispheres. Measuring east-west distances uses longitude lines (not the prime meridian alone), and identifying continents does not rely on these two lines as their core purpose.

Answer:

to separate Earth's four hemispheres