How can we conclude that the Earth is not a perfect sphere based on the acceleration due to gravity?

(N/A) The acceleration due to gravity is given by $g = \frac{GM_e}{R_e^2}$,which implies $g \propto \frac{1}{R_e^2}$. The Earth is slightly bulging at the equator,meaning the radius $R_e$ is larger at the equator,resulting in a lower value of $g$. Conversely,the Earth is flattened at the poles,meaning the radius $R_e$ is smaller at the poles,resulting in a higher value of $g$. Since $g$ varies with latitude,we can conclude that the Earth is not a perfect sphere.