Most physical quantities have units that are combinations of the three fundamental dimensions of length, mass, and time. When these dimensions or measurements are combined, they produce what are referred to as derived units. This means that they have been "derived" from one or more fundamental measurements. These combinations of fundamental measurements can be the combination of the same or different units. The following are examples of various derived units.

Area

Area is the product of two lengths (e.g., width x length for a rectangle); thus, it has the units of length squared, such as square inches (in ²)or square meters (m²).

Volume

Volume is the product of three lengths (e.g., length x width x depth for a rectangular solid); thus, it has the units of length cubed, such as cubic inches (in³) or cubic meters (m³). The MKS and CGS unit systems have a specific unit for volume called the liter (1). One liter is equal to 1000 cubic centimeters (1 1= 1000 cm³).

Density

Density is a measure of the mass of an object per unit volume; thus, it has units of mass divided by length cubed such as kilograms per cubic meter (kg/m³) or pounds per cubic foot (lbs/ft³).

Velocitv

Velocity is the change in length per unit time; thus, it has units such as kilometers per hour (km/h) or feet per second (ft/s).

Acceleration

Acceleration is a measure of the change in velocity or velocity per unit time; thus, it has units such as centimeters per second per second (cm/s²) or feet per second per second (ft/s²).