How many square km is the earth?

Answer

Dear Michael

The formula to calculate the area of ​​a sphere is 4.π.r².

Our planet is not perfectly spherical, it is somewhat flattened. The Earth is widest at the equator. The diameter, that is the distance from one side to the other right through the earth, is 12756.274 km there. Measured between the North and South Poles, the Earth is slightly shorter at 12713,504 km.

To make a good estimate of the surface of the earth, we can take the average of both diameters: 12734.889 km. The radius, r in the formula, is then half that diameter: 6367.4445 km.

The surface area then becomes with the above formula: 509 million km². Of this, about 30% is land and 70% is water.

I hope this is a clear answer to your question.

Kind regards
Peter