Conversion from 100 Decameters to Decimeters

Information about the Decameter (dam)

The decametre is ten metres, written dam. It is a valid SI unit formed with the prefix deca, but like the decimetre it is rarely used. The prefix deca is the only SI multiplier whose symbol is two letters, which makes it slightly awkward to write and may have contributed to its neglect.

Spelling varies. Decametre is the international form; dekameter appears in some American texts, and the symbol dkm is occasionally seen in older material, though dam is the form recognised by the BIPM. The similarity between dam and the abbreviation for decimetre has caused confusion, and some standards bodies discourage the unit for that reason alone.

Where it does appear, it is usually in surveying, forestry and agronomy. Field dimensions, plot spacing and tree heights sit conveniently in the range of a few decametres. Some European cadastral records use the unit. It also occurs in specifications for cable and hose supplied in ten-metre lengths.

The derived area unit is more familiar than the length unit. A square decametre is 100 square metres, which is exactly one are. The are is itself little used, but its hundredfold multiple, the hectare, is the standard measure of land area across most of the world. A hectare is 100 ares, or 10,000 square metres, and can equally be described as a square hectometre.

In practice most people express ten metres simply as ten metres, or as 0.01 kilometres when working at larger scales. The decametre is best understood as a formally correct unit that everyday usage has passed over.

The unit does appear in one everyday context without being named. Swimming pool lane lengths, running track segments and the spacing of street lighting are frequently set in multiples of ten metres. Planning documents that lay out plot frontages or building setbacks often work to the same grid. The quantity is useful; it is only the word that has fallen out of use.

Its square has fared better than the length itself. The are, a hundred square metres, is the square decametre under another name, and although the are is now rare its hundredfold the hectare governs land measurement across most of the world. The same pattern shows in the decare of a thousand square metres, which is the standard unit of farmland in Turkey, Greece, Norway and parts of the Balkans and is simply ten ares. So the decametre survives chiefly by inheritance: nobody quotes a field boundary in decametres, but a great deal of the world's land is bought and sold in units built from it.

One decametre equals 10 metres, 1000 centimetres, or 0.01 kilometres. It is about 32.8084 feet.

Information about the Decimeter (dm)

The decimetre is one tenth of a metre, written dm. It is a legitimate SI-derived unit formed with the prefix deci, but it is among the least used members of the metric ladder. Most people move directly from centimetres to metres and skip the intermediate step entirely.

The reason is practical rather than technical. A length of 3 dm is more naturally expressed as 30 cm or 0.3 m, and neither alternative requires the reader to pause. Units survive when they answer a question no neighbouring unit answers as well, and the decimetre rarely does.

One derived form is a striking exception. The cubic decimetre, dm³, is exactly one litre, because a cube measuring 10 cm on each side holds precisely that volume. This relationship is the foundation of the metric volume system and was deliberate: the litre was defined in 1795 as the volume of a cubic decimetre. The unit therefore appears constantly in chemistry, where concentration is expressed in moles per cubic decimetre, written mol/dm³. School and university chemistry courses use this notation routinely even though the same quantity could be written as moles per litre.

The square decimetre sees occasional use in specifying small areas, particularly in materials testing and in some European technical standards for coatings and surface treatment.

Outside these niches the decimetre appears mainly in teaching, where the full sequence of prefixes is demonstrated, and in tables of unit conversions. Some countries have used it historically for shoe sizing and for textile measurement.

Aquarium and tank capacities show the same relationship at work. A tank measuring five by three by four decimetres holds sixty cubic decimetres, which is sixty litres, and the arithmetic can be done without conversion factors. This is the practical advantage the metric system was designed to deliver, and the decimetre is the length at which volume in litres and length in whole units line up most neatly.

Scandinavia is the exception to its general neglect. Swedish, Norwegian and Danish speakers use the decimetre in ordinary conversation, giving the size of a fish, a shelf or a snowfall in decimetres where a French or German speaker would say tens of centimetres. Schools there teach it alongside the centimetre and the metre rather than skipping it, and rulers are marked accordingly. The habit is a reminder that which prefixes feel natural is a matter of custom rather than logic: the SI offers the whole ladder, and each language community has quietly settled on the rungs it finds comfortable.

One decimetre equals 10 centimetres, 100 millimetres, or 0.1 metres. It is approximately 3.937 inches, a little under four inches.