The degree in longitude is 360 degree which is divided into 180 to the East and 180 to the West. Longitude is a coordinate and an angular measurement which specifies the position of East and West point on our Earth’s surface. However, just because longitude is divided into two does not mean that the longitude of all places is the same.
Longitude is measured through the angle from the Prime Meridian – with Greenwich having the zero point of longitude. You might be asking yourself this question: Why Greenwich? It’s because it was agreed in Washington in1884 that the Prime Meridian which divides the Earth’s hemisphere into eastern and western crosses Greenwich. Hence, it became the official position of zero degrees longitude on Earth.