raadiust
Raadiust is a geometric term denoting the constant distance from the center of a circle or sphere to any point on its boundary. In planar geometry this distance is typically called the radius and is commonly represented by the symbol r. The concept also applies to three-dimensional objects such as spheres, where the raadiust is the same distance from the center to every point on the surface.
In a circle, all raadiusts are equal. The diameter is twice the raadiust (d = 2r). The area
For a sphere, the raadiust is the distance from the center to any point on the surface.
Measurement methods include direct assessment with measuring tools when a center is known, or derivation from
See also: Radius, Diameter, Circumference, Sphere, Polar coordinates.