A circle is a simple geometric shape defined as the set of all points in a plane that are equidistant from a fixed point called the center. The distance from the center to any point on the circle is known as the radius. Circles are commonly found in nature and human-made objects, such as wheels and coins. In mathematics, circles are studied in various contexts, including geometry and trigonometry. The circumference is the distance around the circle, while the area is the space contained within it. The formulas for these measurements are essential for solving problems related to circles in different fields, including engineering and architecture.