A linear measurement assigns a numerical value for the length of an object or between objects. Units of linear measure include inch, foot, meter, kilometer and mile. Linear measurements have one dimension, whereas square measurements have two dimensions and cubic measurements have three.
The foot and the meter represent the two standard units of measure. One foot equals 0.305 meter, and 1 meter is 3.28 feet. For much longer distances, 1 mile equals 5,280 feet and 1 kilometer is 1,000 meters. One mile is 1.61 kilometers and 1 kilometer equals 0.62 mile. Twelve inches equal 1 foot, and 1 inch is 2.54 centimeters.
Two linear measurements that enclose an area create a square measurement. The simplest square measurement is the area of a square. For example, a square with each side 3 feet long is 9 feet squared in area because the length is multiplied by the width for two dimensions.
When a third dimension is added to a square measurement, a cubic measurement results. A cube with 3 feet on each side encloses 27 cubic feet of space because the area measurement is multiplied by three to take into account the height. A cubic measurement multiplies three separate linear measurements including the length, width and height. In this way, linear measurements become volume measurements.