Radius

In geometry, the radius is a straight line from the center of a circle or sphere to its edge or surface. It is a measure of distance that remains constant for any point on the circle or sphere's boundary. In everyday terms, if you imagine a balloon, the radius is like the distance from the center of the balloon to its outer surface. The radius is important because it helps determine other properties of the circle or sphere, such as its area and volume, and provides a consistent way to understand size and proportions.