What is Equatorial Radius?

Answer 1

Half the distance in a straight line from one side of a planet to the other through the centre of the planet with the distance measured from the equaor on both sides. In other words, the radius of the sphere of the planet measured, not at the pole, but at the equator. It is important to distinguish between polar radius and equatorial radius because no planet is an exact sphere, but 'bulges out' at the equator because of 'centrifugal force' as the planet rotates. This is most marked in the gas giants of the solar system especially Jupiter and Saturn, which look distinctly flattened at the poles when viewed through a telescope, so that the polar radii are very much smaller that the equatorial radii.

Answer 2

The equatorial radius is the distance from the center of the Earth to the equator, measuring the Earth's radius at its widest point. It is larger than the polar radius due to the Earth's rotation, resulting in a bulging shape at the equator. The equatorial radius of the Earth is approximately 6,378 kilometers.