Derived quantities are defined in terms of the seven base quantities via a system of quantity equations. The SI derived units for these derived quantities are obtained from these equations and the seven SI base units. 

The International System of Units (SI) specifies a set of seven base units from which all other SI units of measurement are derived. Each of these other units (SI derived units) is either dimensionless or can be expressed as a product of (positive or negative, but usually integral) powers of one or more of the base units. For example, the SI derived unit of area is the square metre (m²), and the SI derived unit of density is the kilogram per cubic metre (kg/m³ or kg m⁻³). Radian and Steradian, though they are dimensionless falls in this category of units. Therefore, they are derived units.