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A foot (plural: feet; symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. Its size can vary from system to system, but in each is around a quarter to a third of a metre. The most commonly used foot today is the international foot. There are 3 feet in a yard and 12 inches in a foot. Cover of brochure The International System of Units. ...
The metre, or meter (U.S.), is a measure of length. ...
km redirects here. ...
A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ...
An angstrom, angström, or ångström (symbol Å) is a non-SI unit that is internationally recognized. ...
The astronomical unit (AU or au or a. ...
A light-year, symbol ly, is the distance light travels in one year: exactly 9. ...
U.S. customary units, commonly known in the United States as English units—but see English unit—or standard units, are units of measurement that are currently used in the USA, in some cases alongside units from SI (the International System of Units—the modern metric system). ...
The Imperial units are an irregularly standardized system of units that have been used in the United Kingdom and its former colonies, including the Commonwealth countries. ...
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
A yard (abbreviation: yd) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
A mile is a unit of length, usually used to measure distance, in a number of different systems, including Imperial units, United States customary units and Norwegian/Swedish mil. ...
This article is not about the symbol for the set of prime numbers, â„™. The prime (′, Unicode U+2032, ′) is a symbol with many mathematical uses: A complement in set theory: A′ is the complement of the set A A point related to another (e. ...
The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day. ...
Length is the long dimension of any object. ...
English unit is an American term that refers to a unit in one of a number of systems of units of measurement, some obsolete, and some still in use. ...
The Imperial units or the Imperial system is a collection of English units, first defined in the Weights and Measures Act of 1824, later refined (until 1959) and reduced. ...
U.S. customary units, commonly known in the United States as English units—but see English unit—or standard units, are units of measurement that are currently used in the USA, in some cases alongside units from SI (the International System of Units—the modern metric system). ...
Orders of magnitude (length) 1 E-13 m 1 E-12 m 1 E-11 m 1 E-10 m 1 E-9 m 1 E-8 m 1 E-7 m 1 E-6 m 1 E-5 m 1 E-4 m 1 E-3 m 1 E...
The metre, or meter (U.S.), is a measure of length. ...
A yard (abbreviation: yd) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
Definition
International foot In 1958 the United States and countries of the Commonwealth of Nations defined the length of the international yard to be 0.9144 metres. Consequently, the international foot is defined to be equal to 0.3048 metres (equivalent to 304.8 millimetres). Year 1958 (MCMLVIII) was a common year starting on Wednesday of the Gregorian calendar. ...
The Commonwealth of Nations (CN), usually known as the Commonwealth, is a voluntary association of 53 independent sovereign states, the majority of which are former colonies of the United Kingdom. ...
A yard (abbreviation: yd) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
The metre, or meter (U.S.), is a measure of length. ...
The metre, or meter (U.S.), is a measure of length. ...
A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ...
The international standard symbol for a foot is "ft" (see ISO 31-1, Annex A). In some cases, the foot is denoted by a prime, which is often approximated by an apostrophe, and the inch by a double prime. For example, 6 feet 2 inches is denoted by 6′2″. This use can cause confusion, because the prime and double prime are also international standard symbols for arcminutes and arcseconds. ISO 31-1 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to space and time. ...
This article is not about the symbol for the set of prime numbers, â„™. The prime (′, Unicode U+2032, ′) is a symbol with many mathematical uses: A complement in set theory: A′ is the complement of the set A A point related to another (e. ...
Look up apostrophe in Wiktionary, the free dictionary. ...
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
This article is not about the symbol for the set of prime numbers, â„™. The prime (′, Unicode U+2032, ′) is a symbol with many mathematical uses: A complement in set theory: A′ is the complement of the set A A point related to another (e. ...
A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. ...
A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...
United States survey foot The United States survey foot is defined as exactly 1200⁄3937 metres, or 0.30480061 m. It is used only in connection with surveys by the U.S. Coast and Geodetic Survey. It is 610 nm greater than the international foot. [1] The metre, or meter (U.S.), is a measure of length. ...
The U.S. Coast and Geodetic Survey was established by President Thomas Jefferson in 1807 as the Survey of the Coast. ...
A metre (American spelling: meter; symbol: m) is a unit of length and the current base unit of length in the International System of Units (SI). ...
The U. S. Survey Foot is used by Land Surveyors and other cartographers for the plans and maps they produce. Each state has a law that states which form of the foot is used for surveys within the given state. The difference is particularly noticeable when converting coordinates that are on the State Plane Coordinate System of the given state. [J. Thaddeus Eldredge, PLS, Massachusetts]
Historical origin The foot as a measure was used in almost all cultures and was usually divided into 12, sometimes 10 inches / thumbs or into 16 fingers / digits. The first known standard foot measure was from Sumer, where a definition is given in a statue of Gudea of Lagash from around 2575 BC. Some metrologists speculate that the imperial foot was adapted from an Egyptian measure by the Greeks, with a subsequent larger foot being adopted by the Romans. Sumer (or Å umer, Sumerian ki-en-gir[1], Egyptian Sanhar[2]) was one of the early civilizations of the Ancient Near East, located in the southern part of Mesopotamia (southeastern Iraq) from the time of the earliest records in the mid 4th millennium BC until the rise of Babylonia in...
Statue of Gudea, British Museum London Gudea was a ruler (ensi) of the city of Lagash in Southern Mesopotamia who ruled ca. ...
Lagash or Sirpurla was one of the oldest cities of Sumer and later Babylonia. ...
(Redirected from 2575 BC) (27th century BC - 26th century BC - 25th century BC - other centuries) (4th millennium BC - 3rd millennium BC - 2nd millennium BC) Events 2900 - 2334 BC – Mesopotamian wars of the Early Dynastic period. ...
For other uses, see Roman Empire (disambiguation). ...
The popular belief is that the original standard was the length of a man’s foot. This is most likely true, but when local authorities and national rulers began calibrating and defining measurements, the foot of no human being was probably used as the basis. In rural regions and without calibrated rulers, many units of measurement were in fact based on the length of some part of body of the person measuring (or for example the area that could be plowed in a day). In that sense, the human foot was no doubt the origin of the measuring unit called a "foot" and was also for a long time the definition of its length. To prevent discord and enable trade, many towns decided on a standard length and displayed this publicly. In order to enable simultaneous use of the different units of length based on different parts of the human body and other "natural" units of length, the different units were redefined as multiples of each other, whereby their lengths no longer corresponded to the original "natural" standards. This process of national standardisation began in Scotland in 1150 and in England in 1303, but many different regional standards had existed in both these countries long before. For other uses, see Foot (disambiguation). ...
Some believe that the original measurement of the English foot was from King Henry I, who had a foot 12 inches long; he wished to standardise the unit of measurement in England. However this is unlikely, because there are records of the word being used approximately 70 years before his birth (Laws Æthelstan). This of course does not exclude the possibility that this old standard was redefined ("calibrated") according to the ruler's foot. In fact, there is evidence that this sort of process was common at least in earlier ages. In other words, a new important ruler could try to impose a new standard for an existent unit, but it is unlikely that any king's foot was ever as long as the modern unit of measurement. Henry I (c. ...
The average foot length is about 9.4 inches (240 mm) for current Europeans. Approximately 99.6% of British men have a foot that is less than 12 inches long. One attempt to "explain" the "missing" inches is that the measure did not refer to a naked foot, but to the length of footwear. This is consistent with the measure being convenient for practical purposes such as on building sites etc. People almost always pace out lengths whilst wearing shoes or boots, rather than removing them and pacing barefoot. A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ...
Walking barefoot Going barefoot is the practice of not wearing shoes, socks, or other foot covering. ...
There are however historical records of definitions of the inch based on the width (not length) of a thumb that are very precise for the standards of the time. One of these was based on an average calculated using three men of different size, thereby enabling surprising accuracy and uniformity throughout a country even without calibrated rulers. It therefore seems likely that at least since about the 12th century the precise length of a foot was in fact based on the inch, not the other way around. Since this length was fairly close to the size of most feet, at least in shoes, this enabled the above-mentioned use of one's shoes in approximating lengths without measuring devices. This sort of imprecise measuring that in addition excessively multiplied the measuring error due to repeated use of a short "ruler" (the foot) was of course never used in surveying and in constructing more complicated buildings.
Trivia While the foot is an ancient measure, it coincidentally matches some common constants (under 2% error). - There are 6076 feet in a nautical mile, which is approximately one minute of arc on the Earth's surface. This makes an arc second, which is 1/60 of an arc minute, about 101 feet.
- The speed of light is 983,571,056.16 feet per second, which makes a foot about 1.017 light nanoseconds.
A nautical mile or sea mile is a unit of length. ...
This article or section does not cite its references or sources. ...
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness. It is the speed of all electromagnetic radiation in a vacuum, not just visible light. ...
To help compare orders of magnitude of different times this page lists times between 10−9 seconds and 10−8 seconds (1 nanosecond and 10 nanoseconds) See also times of other orders of magnitude. ...
See also The definition, agreement and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day. ...
Units of measurement were among the earliest tools invented by humans. ...
// The metric system Metric systems of units have evolved since the adoption of the first well-defined system in France in 1791. ...
Weights and measures is a term used by legal authorities in English speaking countries such as the United Kingdom for a function related to units of measurement in trade. ...
English unit is an American term that refers to a unit in one of a number of systems of units of measurement, some obsolete, and some still in use. ...
The Imperial units or the Imperial system is a collection of English units, first defined in the Weights and Measures Act of 1824, later refined (until 1959) and reduced. ...
U.S. customary units, commonly known in the United States as English units—but see English unit—or standard units, are units of measurement that are currently used in the USA, in some cases alongside units from SI (the International System of Units—the modern metric system). ...
Cover of brochure The International System of Units. ...
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