Question

all lines of longitude are circle

Answer 1

Answer:

all lines of longitude are called meridians whereas all the lines of latitude are called circle

Answer 2

All the meridians on Earth are great circles. Meridians, including the prime meridian, are the north-south lines we use to help describe exactly where we are on the Earth. All these lines of longitude meet at the poles, cutting the Earth neatly in half. The Equator is another of the Earth's great circles.