raadius
Raadius is the distance from the center of a circle or sphere to any point on its boundary. In two dimensions, this distance defines the circle’s radius; in three dimensions it defines the sphere’s radius. The symbol r is standard, though other variables may appear in different contexts.
For a circle of radius r, the circumference equals 2πr and the area equals πr^2. In a
In higher dimensions, the concept extends to n-dimensional balls, where the radius is still the distance from
Linguistically, raadius is the Estonian term for radius and is used in similar mathematical contexts as the
See also: Circle, Sphere, Diameter, Circumference, Surface area, Volume, Radius vector.