What is the distance from the center of a circle to its circumference called?

The distance from the center of a circle to its circumference is called the radius. This is a fundamental concept in circle geometry, where the radius is defined as half the diameter. The radius is crucial because it helps to determine various characteristics and measurements of a circle, including its area and circumference.

In mathematical terms, the area of a circle is calculated using the radius, as is the formula for the circumference, which is 2 times π times the radius. Understanding the radius is essential for effectively working with circles in both theoretical and practical applications, such as engineering and design.

The other terms have specific meanings that do not represent the distance from the center to the circumference: the diameter refers to the longest distance across the circle, passing through the center, the circumference is the total distance around the circle, and the area represents the space contained within the circle. Recognizing these definitions helps in distinguishing the radius from other related terms.