The earth is an elliptical spheroid, which means that the earth is a solid object that is approximately the same shape as a sphere.
It is proved that the earth is spherical in shape, but because it is a little flattened at the poles, the shape is called geoid. The earth has the following dimensions:
Equatorial circumference – 40,084 km
Equatorial diameter – 12,761 km
Polar circumference – 3,955 km
Polar diameter – 12,722 km