At the equator a degree of latitude and a degree of longitude are approximately equal, but at 49 degrees north, a degree of longitude measures 71.8 km and a degree of latitude measures 111 km. why does this difference exist? (2)

This difference exists because of the Earth's slight elipsoid shape.

Explanation:

This difference exists because of the Earth's slight elipsoid shape.

Due to this reason, the measurement of a degree of longitude is given by the following formula.

In which is the length in degrees at the Equator and La is the latitude(in degrees).