The equator.
Small circles on the Earth are lines of latitude that do not align with the equator, which is the largest circle. These circles are parallel to the equator and include lines such as the Tropics of Cancer and Capricorn as well as the Arctic and Antarctic Circles. Unlike great circles, which divide the Earth into two equal halves, small circles vary in size and are used in navigation and mapping to denote specific latitudes. They represent points of equal latitude but differ in circumference as you move away from the equator.
The equator and all lines of longitude are called great circles because the represent the circumference of the earth. The other latitude lines along the globe are smaller then the actually circumference.
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.
circumference = 2*pi*radius or pi*diameter
It is an arc
An arc
The converse of the statement "If two circles have the same diameter, then they have the same circumference" is "If two circles have the same circumference, then they have the same diameter." This means that if you know two circles share identical circumferences, you can conclude that their diameters are also equal.
The circumference of a circle = pi*diametre = 2pi*radius
The largest circumference in the solar system belongs to the planet Jupiter, which has a circumference of about 439,264 kilometers (273,600 miles) at its equator. In terms of Earth, the largest circumference is approximately 40,075 kilometers (24,901 miles) around the equator. If considering man-made objects, the Great Wall of China has a total length of about 21,196 kilometers (13,171 miles).
Pi times the diameter of a circle gives its circumference.
The ratio of the circumference of a circle to its diameter is Pi. (3.14159)
Then they are similar.