Describe how the distance of a degree of longitude varies from the equator to the poles?

The degree of latitude is widest at equator and converses at pole thus, it is zero at pole.

Explanation:

For the latitudes, the lines are parallel to each other and each latitude are approximately 111 km apart. But, due to the elliptical shape of earth, the earth is wide at center and narrow at poles. Due to this the calculation of longitude varies for each longitude.

We use cosine component to mathematically measure distance between the longitudes.