Question

why longitudes are called semicircles​

Answer 1

Answer:

Each great circle passing through the north and south poles has the earth's axis as its diameter. Each great circle is divided by the poles into two semi-circles called meridians of longitude. As the meridians run north and south, places having the same longitude will be due or due south of each other.

Answer 2

Each great circle passing through the north and south poles has the earth's axis as its diameter. Each great circle is divided by the poles into two semi-circles called meridians of longitude. As the meridians run north and south, places having the same longitude will be due or due south of each other.