The distance around a circle is called the circumference. It can be calculated using the formula C = 2πr, where C represents the circumference and r symbolizes the radius of the circle. Alternatively, it can also be determined using the diameter (d) with the formula C = πd. Understanding circumference is important in various fields, including geometry, engineering, and real-world applications like construction and manufacturing. The concept of circumference is essential to grasp circular shapes, allowing for calculations related to area, distance, and movement in rotational contexts.