Millimeters to Decameters (mm to dam)

1 millimeter equals 0.0001 decameters exactly.

1 millimeter = 0.0001 decameters

How to convert millimeters to decameters

To convert millimeters to decameters, multiply the number of millimeters by 0.0001. This factor is exact. To go the other way, multiply decameters by 10,000.

decameters = millimeters × 0.0001

Example: 10 millimeters = 0.001 decameters.

About these units

Millimeter (mm)

Metric (SI)Current unit

One thousandth of a meter. Used in engineering, manufacturing and rainfall measurement.

Carl Friedrich Gauss put the millimeter at the base of his 1832 proposal for absolute units, pairing it with the milligram and the second, although the centimeter-based CGS system later won out among scientists. The name combines the metric prefix milli-, from the Latin for one thousand, with the meter. Since 1983 a millimeter has been tied to the speed of light: it is the distance light covers in 1/299,792,458,000 of a second.

Millimeters are the language of fine mechanical work. Standard rulers are divided into them, digital calipers commonly read to 0.01 mm, and mechanical pencil leads come in 0.5 and 0.7 mm. Copy paper is about 0.1 mm thick, and a thin hair, at 0.02 to 0.04 mm across, is close to the smallest thing the naked eye can see. A wave with a frequency of 300 GHz has a wavelength of 1 mm. An inch is exactly 25.4 mm. One trap for readers in the United States is that mil there traditionally means a thousandth of an inch, not a millimeter.

1 millimeter = 0.001 meters (exactly).

Sources: Wikipedia: Millimetre; Wikipedia: Centimetre-gram-second system of units; NIST Guide to the SI, Appendix B.8: conversion factors

Decameter (dam)

Metric (SI)Current unit

10 meters. An official SI prefix combination that is rarely used.

Spelling is the first complication with this unit. The BIPM and most English-speaking countries write decametre or decameter with the symbol dam, while NIST and American style guides prefer deka, as in dekameter. Both mean ten meters, which is about 10.94 yards or 393.7 inches. Wikipedia's article says little about the unit's history, so no dates are given here.

Meteorologists find it practical for expressing the altitude of geopotential heights. The cubic decameter is used for large water volumes, because one cubic decameter is 1,000 cubic meters, or one megaliter. The are, an older metric land measure, is a square decameter, equal to 100 square meters. One technical atmosphere is also the pressure of a decameter of water. In the metric length series it sits between the meter and the hectometer at 100 m.

1 decameter = 10 meters (exactly).

Sources: Wikipedia: Decametre; NIST: metric (SI) prefixes; Wikipedia: Metric prefix

Related conversions

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