The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...

A sphere is a perfectly round solid figure. All points on the surface of the shape are the same distance away from the centre – we call this distance the radius. The formula for the volume and surface ...

A small sphere resting atop a large sphere begins to slide to the right. The large sphere has a diameter of ten meters. The small sphere has a diameter of one meter. Initially the small sphere remains ...