A ring, often referred to as a circle, is a two-dimensional shape where all points are equidistant from a central point. This central point is known as the center of the circle, and the distance from the center to any point on the circle is called the radius. The total distance around the circle is known as the circumference, which can be calculated using the formula C = 2\pi r, where r is the radius. In geometry, circles are fundamental shapes and are studied in various contexts, including mathematics, art, and engineering. They can be found in everyday objects, such as wheels and coins, and have unique properties, such as having no corners or edges. Circles also play a significant role in trigonometry and physics, where they help describe periodic phenomena.