You can infer the actual shape of the Earth from a set of polar and equatorial diameters that show a difference between the two.

Here's why:

* Earth is not perfectly spherical: It's an oblate spheroid, meaning it's slightly flattened at the poles and bulging at the equator.

* Polar diameter: The distance across the Earth through the poles.

* Equatorial diameter: The distance across the Earth through the equator.

Therefore, if the equatorial diameter is greater than the polar diameter, it confirms that Earth is indeed an oblate spheroid.

Let me know if you have any other questions.