The steradian is a unit of solid angle defined as the solid angle subtended at the center of a sphere by a portion of the surface of the sphere that has an area equal to the square of the radius of the sphere.
The steradian is a unit of solid angle defined as the solid angle subtended at the center of a sphere by a portion of the surface of the sphere that has an area equal to the square of the radius of the sphere. The steradian is a derived unit in the International System of Units.