Why the lines of latitudes decrease in size towards the poles?

Lines of latitude, or parallels, are imaginary circles that run parallel to the equator. As you move from the equator towards the poles, these circles decrease in circumference due to the Earth's spherical shape. At the equator, the latitude is 0 degrees and the circumference is largest, while at the poles, the lines converge to a single point at 90 degrees north and south, resulting in their diminishing size. This geometric property is a direct consequence of the Earth's curvature.