Question

The length of the latitude gradually decreased from the equator to the poles Why?

Answer 1

the length of latitude gradually decrease towards the poles because

this is due to the rotation of the earth because as the earth rotates a cetrifugal force is devloped which cause change in its shape

that makes it geoid or oblagate spherioid .And latitude is a circles horizontal to its orbital plane. In any sphere the circumference is lengthier at 0°. So equator is lengthiest latitude and the degree increases or move away from equator to pole the circumference of globe decreases hence latitudinal length also decreases.