The steradian is a unit of solid-angle measure in the International System of Units (SI). It is defined as
- the solid angle of a sphere subtended by a portion of the surface whose area is equal to the square of the sphere’s radius.
The complete surface area of a sphere is 4π times the square of its radius and
- the total solid angle about a point is equal to 4π steradians.
Mathematical rules and laws - numbers, areas, volumes, exponents, trigonometric functions and more.
Converting between angle units.
Convert from minutes to degrees.
Convert between Cartesian and Polar coordinates.
Radian is the SI unit of angle. Convert between degrees and radians. Calculate angular velocity.
An introduction to the SI metric system.