# radius

The radius of a circle or sphere is the distance from the center of the figure to the outer edge (or surface.)

This definition actually holds in $n$ dimensions; so 4th and 5th and $k$-dimensional “spheres” have radii. Since a circle is really a 2-dimensional sphere, its “radius” is merely an instance of the general definition.

Title radius Radius 2013-03-22 12:21:02 2013-03-22 12:21:02 akrowne (2) akrowne (2) 5 akrowne (2) Definition msc 51-00 Diameter2