A foot (plural: feet or foot;^[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a non-SI unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. A yard (abbreviation yd) is a unit of Length in several different systems including English units Imperial units and United Inches redirects here To see the Les Savy Fav album see Inches. The prime symbol ( ′  double prime symbol ( &Prime  triple prime symbol ( ‴  etc Length is the long Dimension of any object The length of a thing is the distance between its ends its linear extent as measured from end to end English unit is the American name for a unit in one of a number of systems of Units of measurement, some obsolete and some still in use in present-day USA, the Imperial units or the Imperial system is a collection of units first defined in the British Weights and Measures Act of 1824 US customary units, also known in the United States as English units or Imperial units (in reference to the British Empire) (but see English Its size can vary from system to system, but in each is around a quarter to a third of a metre. To help compare different Orders of magnitude this page lists lengths between 10&minus1 m and 1 m (10 cm and 1 m The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International The most commonly used foot today is the international foot. There are 3 feet in a yard and 12 inches in a foot. A yard (abbreviation yd) is a unit of Length in several different systems including English units Imperial units and United Inches redirects here To see the Les Savy Fav album see Inches.

Contents 1 Definition 1.1 International foot 1.2 United States survey foot 2 Historical origin 3 See also 4 External links 5 Notes

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. Year 1958 ( MCMLVIII) was a Common year starting on Wednesday (link will display full calendar of the Gregorian calendar. The United States of America —commonly referred to as the A yard (abbreviation yd) is a unit of Length in several different systems including English units Imperial units and United 9144 metres. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International Consequently, the international foot is defined to be equal to 0. 3048 metres (equivalent to 304. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International 8 millimetres). The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to

The international standard symbol for a foot is "ft" (see ISO 31-1, Annex A). ISO 31-1 is the part of International standard ISO 31 that defines names and symbols for quantities and units related to Space In some cases, the foot is denoted by a prime, which is often approximated by an apostrophe, and the inch by a double prime. The prime symbol ( ′  double prime symbol ( &Prime  triple prime symbol ( ‴  etc Inches redirects here To see the Les Savy Fav album see Inches. The prime symbol ( ′  double prime symbol ( &Prime  triple prime symbol ( ‴  etc For example, 2 feet 2 inches is denoted by 2′2″. This use can cause confusion, because the prime and double prime are also international standard symbols for arcminutes and arcseconds. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. The symbol ft is shared with that for the femtotonne. This article is about the tonne or metric ton For other tons see Ton.

United States survey foot

The United States survey foot is defined as exactly ¹²⁰⁰⁄₃₉₃₇ metres, approximately 0. The United States of America —commonly referred to as the The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International 30480061 m. It is used in connection with surveying and mapping. It is exactly 1,000,000 / 999,998 times the international foot and thus 610 nm greater than the international foot. A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a ^[2]

The small difference between the survey and international feet would not be detectable on a survey of a small parcel, but becomes significant for mapping, or when a state plane coordinate system is used, because the origin of the system may be hundreds of miles from the point of interest. The State Plane Coordinate System (SPS or SPCS is a set of 126 geographic zones or Coordinate systems designed for specific regions of the United States. In 1986 the National Geodetic Survey (NGS) released the North American Datum of 1983, which underlies the state plane coordinate systems. The National Geodetic Survey and the Office of Coast Survey are the two successor agencies in the United States to the U The North American Datum is the official datum used for the primary Geodetic network in North America An NGS policy from 1991 has this to say about the units used with the new datum:

In preparation for the adjustment of the North American Datum of 1983, 31 states enacted legislation for the State Plane Coordinate System of 1983 (SPCS 83). All states defined SPCS 83 with metric parameters. Within the legislation, the U. S. Survey Foot was specified in 11 states and the International Foot was specified in 6 states. In all other states the meter is the only referenced unit of measure in the SPCS 83 legislation. The remaining 19 states do not yet have any legislation concerning SPCS 83. ^[3]

Historical origin

The foot as a measure was used in almost all western 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. Sumer ( Sumerian: sux-Latn [[Ki (earth ki]]-[[EN (cuneiform en]]-'''ĝir15''', Akkadian: Šumeru; possibly Biblical Shinar Gudea was a ruler ( ensi) of the city of Lagash in Southern Mesopotamia who ruled ca Lagash ( is modern Tell al-Hiba, Iraq. Located northwest of the junction of the Euphrates and Tigris rivers and east of Uruk The 26th century BC is a Century which lasted from the year 2600 BC to 2501 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. This article is about the country of Egypt For a topic outline on this subject see List of basic Egypt topics. The term ancient Greece refers to the period of Greek history lasting from the Greek Dark Ages ca The Roman Empire was the post-Republican phase of the ancient Roman civilization, characterised by an autocratic form of government and large territorial

Some of the earliest records of the use of the foot come from the region of ancient Greece. The originators devised, or perhaps borrowed from Egypt, the degree of longitude, divided the circumference of the earth into 360 degrees, and subdivided the degree for shorter distances. One degree of longitude comprised 600 stadia. One stadion was divided into 600 feet. Thus the degree of longitude measured 360,000 feet. One mile was 10 stadia or 6000 feet. This is essentially the same mile that was (or still is) used in the Western hemisphere, but the modern foot is longer than the original.

The popular belief is that the original standard was the length of a man’s foot. The foot is an Anatomical structure found in many Animals It is the terminal portion of a limb which bears weight and allows Locomotion. 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 ploughed 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.

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. Henry I (c 1068/1069 – 1 December 1135) was the fourth son of William I the Conqueror, the first King of England after the Norman 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.

The average foot length is about 9. 4 inches (240 mm) for current Europeans. The Millimetre ( American spelling: millimeter, symbol mm) is a unit of Length in the Metric system, equal to 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, which could theoretically add an inch or two to the naked foot's length. This is consistent with the measure being convenient for practical uses such as building sites. People almost always pace out lengths whilst wearing shoes or boots, rather than removing them and pacing barefoot. For people with the name Barefoot see Barefoot (surname Going barefoot (also barefoot ed) means for a person not to use or

There are however historical records of definitions of the inch based on the width (not length) of a man's 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 never used in surveying and in constructing more complicated buildings.

See also

• Units of measurement
• History of measurement
• Systems of measurement
• Weights and measures
• English unit
• Imperial unit
• United States customary units
• International System of Units
• Inch

External links

• http://www.knowledgedoor.com/1/Library_of_Units_and_Constants/Group_Index/foot_group.htm

Notes

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