A unit of measure of solid angles. Formally, it is the angle subtended at the center of the sphere by a portion of the surface whose area is equal to the square of the radius of the sphere. There are 4 pi steradians in a sphere.

the standard unit of solid angle measure in mathematics. Just as there are 2 pi radians in a circle, there are 4 pi steradians in a sphere. Thus one steradian equals about 0.079 577 sphere. There are 129 600/ pi = 41 252.96 square degrees in a sphere, so 1 steradian also equals about 3282.806 square degrees. The unit originated in the 1870s by analogy with the radian.

(str) A solid angle with vertex at the center of a sphere of radius r that encompasses an area of r2 on the surface of the sphere.

The unit of measure for a solid angle.

the unit of solid angle adopted under the Systeme International d'Unites

a conical figure, or solid angle, whose intersection with a unit sphere covers one unit area

a measure of solid angle, in the same way that a radian measures angles

a solid angle at the centre of sphere of one metre radius that is subtended by one square metre of the surface

a unit area of a spherical surface with a unit radius

A steradian is defined as the solid (spatial) angle which, having its vertex at the center of the sphere, cuts off an area equal to the square of its radius. So, 1 steradian has a projected area of 1 square meter at a distance of 1 meter, etc. A sphere contains 4*pi steradians.

The solid angle that cuts unit area from the surface of a sphere of unit radius centred at the vertex of the solid angle. There are 4(pi )sr in a sphere.

The solid angle subtended at the center of a sphere by an area on the surface of the sphere equal to the square of the sphere radius.

Unit of solid angle. An entire sphere has 4B steradians.

Solid angle subtending an area on the surface of a sphere equal to the square of the radius. There is 4n steradian in a sphere.

A unit solid angle on the surface of a sphere equal to the square of the sphere's radius.

Steradian is the solid angle that, having its vertex in the center of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.

the unit of solid angle. There are 4*pi steradians in the entire celestial sphere. One square degree is (1/57.3)2 steradians because one degree is (1/57.3) radians.

The unit of measure of solid angles, equal to the angle subtended at the center of a sphere.

A unit of solid angle. A complete sphere subtends 4 steradians from the centre.

The steradian (symbol: sr) is the SI unit of solid angle. It is used to describe two-dimensional angular spans in three-dimensional space, analogous to the way in which the radian describes angles in a plane. The name is partly derived from the Greek stereos for "solid".