The longitude, which almost bisects Africa into two equal halves, east and west, is longitude
Answer Details
Africa extends roughly from about 17 degrees W at its westernmost point (Cape Verde, Senegal) to about 51 degrees E at its easternmost point (Cape Guardafui, Somalia). To find the longitude that bisects the continent into approximately equal eastern and western halves, we look for the meridian near the middle of this range.
The longitude of 20 degrees E runs through the heart of Africa, passing through countries such as Libya, Chad, Cameroon, the Democratic Republic of Congo, and Namibia. It divides the continent into roughly equal portions to the east and west.
The other options do not bisect Africa equally:
20 degrees W lies in the Atlantic Ocean, west of the African mainland.
40 degrees E passes through the eastern part of Africa (Ethiopia, Kenya, Tanzania), leaving the vast majority of the continent to the west.
40 degrees W lies deep in the Atlantic Ocean, far from Africa.