Final answer:
The radius of a sphere is the distance from its center to its surface, used in various calculations such as volume and area.
Step-by-step explanation:
The radius of a sphere is the distance from the center of the sphere to any point on its surface. To calculate the volume of a sphere, you use the formula V = (4/3)π(r)³, where 'r' is the radius.
Similarly, the surface area is given by the formula A = 4π(r)².
Consider the Earth, for instance, which has an average radius of approximately 6371 km.
The concept of radius is also applied in other contexts, such as the radius of curvature of a spherical mirror where R refers to this radius, affecting the mirror's focal length.