1.
Hectárea
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The hectare is an SI accepted metric system unit of area equal to 100 ares and primarily used in the measurement of land as a metric replacement for the imperial acre. An acre is about 0.405 hectare and one hectare contains about 2.47 acres, in 1795, when the metric system was introduced, the are was defined as 100 square metres and the hectare was thus 100 ares or 1⁄100 km2. When the metric system was further rationalised in 1960, resulting in the International System of Units, the are was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI units, the metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. At the first meeting of the CGPM in 1889 when a new standard metre, manufactured by Johnson Matthey & Co of London was adopted, in 1960, when the metric system was updated as the International System of Units, the are did not receive international recognition. The units that were catalogued replicated the recommendations of the CGPM, many farmers, especially older ones, still use the acre for everyday calculations, and convert to hectares only for official paperwork. Farm fields can have long histories which are resistant to change, with names such as the six acre field stretching back hundreds of years. The names centiare, deciare, decare and hectare are derived by adding the standard metric prefixes to the base unit of area. The centiare is a synonym for one square metre, the deciare is ten square metres. The are is a unit of area, equal to 100 square metres and it was defined by older forms of the metric system, but is now outside of the modern International System of Units. It is commonly used to measure real estate, in particular in Indonesia, India, and in French-, Portuguese-, Slovakian-, Serbian-, Czech-, Polish-, Dutch-, in Russia and other former Soviet Union states, the are is called sotka. It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large, the decare is derived from deka, the prefix for 10 and are, and is equal to 10 ares or 1000 square metres. It is used in Norway and in the former Ottoman areas of the Middle East, the hectare, although not strictly a unit of SI, is the only named unit of area that is accepted for use within the SI. The United Kingdom, United States, Burma, and to some extent Canada instead use the acre, others, such as South Africa, published conversion factors which were to be used particularly when preparing consolidation diagrams by compilation. In many countries, metrication redefined or clarified existing measures in terms of metric units, non-SI units accepted for use with the International System of Units

2.
Unidad de medida
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A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same quantity. Any other value of quantity can be expressed as a simple multiple of the unit of measurement. For example, length is a physical quantity, the metre is a unit of length that represents a definite predetermined length. When we say 10 metres, we actually mean 10 times the definite predetermined length called metre, 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. Different systems of units used to be very common, now there is a global standard, the International System of Units, the modern form of the metric system. In trade, weights and measures is often a subject of regulation, to ensure fairness. The International Bureau of Weights and Measures is tasked with ensuring worldwide uniformity of measurements, metrology is the science for developing nationally and internationally accepted units of weights and measures. In physics and metrology, units are standards for measurement of quantities that need clear definitions to be useful. Reproducibility of experimental results is central to the scientific method, a standard system of units facilitates this. Scientific systems of units are a refinement of the concept of weights, science, medicine, and engineering often use larger and smaller units of measurement than those used in everyday life and indicate them more precisely. The judicious selection of the units of measurement can aid researchers in problem solving, in the social sciences, there are no standard units of measurement and the theory and practice of measurement is studied in psychometrics and the theory of conjoint measurement. A unit of measurement is a quantity of a physical property. Units of measurement were among the earliest tools invented by humans, primitive societies needed rudimentary measures for many tasks, constructing dwellings of an appropriate size and shape, fashioning clothing, or bartering food or raw materials. Weights and measures are mentioned in the Bible and it is a commandment to be honest and have fair measures. As of the 21st Century, multiple unit systems are used all over the world such as the United States Customary System, the British Customary System, however, the United States is the only industrialized country that has not yet completely converted to the Metric System. The systematic effort to develop an acceptable system of units dates back to 1790 when the French National Assembly charged the French Academy of Sciences to come up such a unit system. After this treaty was signed, a General Conference of Weights, the CGPM produced the current SI system which was adopted in 1954 at the 10th conference of weights and measures. Currently, the United States is a society which uses both the SI system and the US Customary system

3.
Área
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Area is the quantity that expresses the extent of a two-dimensional figure or shape, or planar lamina, in the plane. Surface area is its analog on the surface of a three-dimensional object. It is the analog of the length of a curve or the volume of a solid. The area of a shape can be measured by comparing the shape to squares of a fixed size, in the International System of Units, the standard unit of area is the square metre, which is the area of a square whose sides are one metre long. A shape with an area of three square metres would have the area as three such squares. In mathematics, the square is defined to have area one. There are several formulas for the areas of simple shapes such as triangles, rectangles. Using these formulas, the area of any polygon can be found by dividing the polygon into triangles, for shapes with curved boundary, calculus is usually required to compute the area. Indeed, the problem of determining the area of plane figures was a motivation for the historical development of calculus. For a solid such as a sphere, cone, or cylinder. Formulas for the areas of simple shapes were computed by the ancient Greeks. Area plays an important role in modern mathematics, in addition to its obvious importance in geometry and calculus, area is related to the definition of determinants in linear algebra, and is a basic property of surfaces in differential geometry. In analysis, the area of a subset of the plane is defined using Lebesgue measure, in general, area in higher mathematics is seen as a special case of volume for two-dimensional regions. Area can be defined through the use of axioms, defining it as a function of a collection of certain plane figures to the set of real numbers and it can be proved that such a function exists. An approach to defining what is meant by area is through axioms, area can be defined as a function from a collection M of special kind of plane figures to the set of real numbers which satisfies the following properties, For all S in M, a ≥0. If S and T are in M then so are S ∪ T and S ∩ T, if S and T are in M with S ⊆ T then T − S is in M and a = a − a. If a set S is in M and S is congruent to T then T is also in M, every rectangle R is in M. If the rectangle has length h and breadth k then a = hk, let Q be a set enclosed between two step regions S and T

4.
Cuadrado
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In geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles. It can also be defined as a rectangle in which two adjacent sides have equal length, a square with vertices ABCD would be denoted ◻ ABCD. e. A rhombus with equal diagonals a convex quadrilateral with sides a, b, c, d whose area is A =12 =12. Opposite sides of a square are both parallel and equal in length, all four angles of a square are equal. All four sides of a square are equal, the diagonals of a square are equal. The square is the n=2 case of the families of n-hypercubes and n-orthoplexes, a truncated square, t, is an octagon. An alternated square, h, is a digon, the perimeter of a square whose four sides have length ℓ is P =4 ℓ and the area A is A = ℓ2. In classical times, the power was described in terms of the area of a square. This led to the use of the square to mean raising to the second power. The area can also be calculated using the diagonal d according to A = d 22. In terms of the circumradius R, the area of a square is A =2 R2, since the area of the circle is π R2, in terms of the inradius r, the area of the square is A =4 r 2. Because it is a polygon, a square is the quadrilateral of least perimeter enclosing a given area. Dually, a square is the quadrilateral containing the largest area within a given perimeter. Indeed, if A and P are the area and perimeter enclosed by a quadrilateral, then the isoperimetric inequality holds,16 A ≤ P2 with equality if. The diagonals of a square are 2 times the length of a side of the square and this value, known as the square root of 2 or Pythagoras constant, was the first number proven to be irrational. A square can also be defined as a parallelogram with equal diagonals that bisect the angles, if a figure is both a rectangle and a rhombus, then it is a square. If a circle is circumscribed around a square, the area of the circle is π /2 times the area of the square, if a circle is inscribed in the square, the area of the circle is π /4 times the area of the square. A square has an area than any other quadrilateral with the same perimeter

5.
Kilómetro
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The kilometre or kilometer is a unit of length in the metric system, equal to one thousand metres. K is occasionally used in some English-speaking countries as an alternative for the kilometre in colloquial writing. A slang term for the kilometre in the US military is klick, there are two common pronunciations for the word. It is generally preferred by the British Broadcasting Corporation and the Australian Broadcasting Corporation, many scientists and other users, particularly in countries where the metric system is not widely used, use the pronunciation with stress on the second syllable. The latter pronunciation follows the pattern used for the names of measuring instruments. The problem with this reasoning, however, is that the meter in those usages refers to a measuring device. The contrast is more obvious in countries using the British rather than American spelling of the word metre. When Australia introduced the system in 1975, the first pronunciation was declared official by the governments Metric Conversion Board. However, the Australian prime minister at the time, Gough Whitlam, by the 8 May 1790 decree, the Constituent assembly ordered the French Academy of Sciences to develop a new measurement system. In August 1793, the French National Convention decreed the metre as the length measurement system in the French Republic. The first name of the kilometre was Millaire, although the metre was formally defined in 1799, the myriametre was preferred to the kilometre for everyday use. The term myriamètre appeared a number of times in the text of Develeys book Physique dEmile, ou, Principes de la de la nature. French maps published in 1835 had scales showing myriametres and lieues de Poste, the Dutch, on the other hand, adopted the kilometre in 1817 but gave it the local name of the mijl. It was only in 1867 that the term became the only official unit of measure in the Netherlands to represent 1000 metres. In the US, the National Highway System Designation Act of 1995 prohibits the use of highway funds to convert existing signs or purchase new signs with metric units. Although the State DOTs had the option of using metric measurements or dual units, all of them abandoned metric measurements, the Manual on Uniform Traffic Control Devices since 2000 is published in both metric and American Customary Units. Some sporting disciplines feature 1000 m races in major events, but in other disciplines, even though records are catalogued

6.
Sistema Internacional de Unidades
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The International System of Units is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units, the system also establishes a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units. The system was published in 1960 as the result of an initiative began in 1948. It is based on the system of units rather than any variant of the centimetre-gram-second system. The motivation for the development of the SI was the diversity of units that had sprung up within the CGS systems, the International System of Units has been adopted by most developed countries, however, the adoption has not been universal in all English-speaking countries. The metric system was first implemented during the French Revolution with just the metre and kilogram as standards of length, in the 1830s Carl Friedrich Gauss laid the foundations for a coherent system based on length, mass, and time. In the 1860s a group working under the auspices of the British Association for the Advancement of Science formulated the requirement for a coherent system of units with base units and derived units. Meanwhile, in 1875, the Treaty of the Metre passed responsibility for verification of the kilogram, in 1921, the Treaty was extended to include all physical quantities including electrical units originally defined in 1893. The units associated with these quantities were the metre, kilogram, second, ampere, kelvin, in 1971, a seventh base quantity, amount of substance represented by the mole, was added to the definition of SI. On 11 July 1792, the proposed the names metre, are, litre and grave for the units of length, area, capacity. The committee also proposed that multiples and submultiples of these units were to be denoted by decimal-based prefixes such as centi for a hundredth, on 10 December 1799, the law by which the metric system was to be definitively adopted in France was passed. Prior to this, the strength of the magnetic field had only been described in relative terms. The technique used by Gauss was to equate the torque induced on a magnet of known mass by the earth’s magnetic field with the torque induced on an equivalent system under gravity. The resultant calculations enabled him to assign dimensions based on mass, length, a French-inspired initiative for international cooperation in metrology led to the signing in 1875 of the Metre Convention. Initially the convention only covered standards for the metre and the kilogram, one of each was selected at random to become the International prototype metre and International prototype kilogram that replaced the mètre des Archives and kilogramme des Archives respectively. Each member state was entitled to one of each of the prototypes to serve as the national prototype for that country. Initially its prime purpose was a periodic recalibration of national prototype metres. The official language of the Metre Convention is French and the version of all official documents published by or on behalf of the CGPM is the French-language version

7.
Acre (unidad de superficie)
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The acre is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain by 1 furlong, lucia, St. Helena, St. Kitts and Nevis, St. Vincent and the Grenadines, Turks and Caicos, the United Kingdom, the United States and the US Virgin Islands. The international symbol of the acre is ac, the most commonly used acre today is the international acre. In the United States both the international acre and the US survey acre are in use, but differ by two parts per million, see below. The most common use of the acre is to measure tracts of land, one international acre is defined as exactly 4,046.8564224 square metres. An acre was defined in the Middle Ages, being the amount of land that could be ploughed in one day with a yoke of oxen. One acre equals 0.0015625 square miles,4,840 square yards,43,560 square feet or about 4,047 square metres. While all modern variants of the acre contain 4,840 square yards, there are definitions of a yard. A square enclosing one acre is approximately 69.57 yards, as a unit of measure, an acre has no prescribed shape, any area of 43,560 square feet is an acre. In the international yard and pound agreement of 1959 the United States, consequently, the international acre is exactly 4,046.8564224 square metres. The US survey acre is about 4,046.872609874252 square metres, its value is based on an inch defined by 1 metre =39.37 inches exactly. Surveyors in the United States use both international and survey feet, and consequently, both varieties of acre. Since the difference between the US survey acre and international acre is only about a quarter of the size of an A4 sheet of paper, areas are seldom measured with sufficient accuracy for the different definitions to be detectable. In India, residential plots are measured in cents or decimal, in Sri Lanka the division of an acre into 160 perches or 4 roods is common. To be more exact, one acre is 90.75 percent of a 100 yards long by 53.33 yards wide American football field, the full field, including the end zones, covers approximately 1.32 acres. For residents of countries, the acre might be envisaged as approximately half of a 105 metres long by 68 metres wide association football pitch. It may also be remembered as 44,000 square feet, in English it was historically spelled aker. The acre was approximately the amount of land tillable by a yoke of oxen in one day and this explains one definition as the area of a rectangle with sides of length one chain and one furlong

8.
Ciudad del Vaticano
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Vatican City, officially Vatican City State or the State of Vatican City, is a walled enclave within the city of Rome. With an area of approximately 44 hectares, and a population of 842, however, formally it is not sovereign, with sovereignty being held by the Holy See, the only entity of public international law that has diplomatic relations with almost every country in the world. It is an ecclesiastical or sacerdotal-monarchical state ruled by the Bishop of Rome – the Pope, the highest state functionaries are all Catholic clergy of various national origins. Vatican City is distinct from the Holy See, which dates back to early Christianity and is the episcopal see of 1.2 billion Latin. According to the terms of the treaty, the Holy See has full ownership, exclusive dominion, within Vatican City are religious and cultural sites such as St. Peters Basilica, the Sistine Chapel and the Vatican Museums. They feature some of the worlds most famous paintings and sculptures, the unique economy of Vatican City is supported financially by the sale of postage stamps and tourist mementos, fees for admission to museums, and the sale of publications. The name Vatican City was first used in the Lateran Treaty, signed on 11 February 1929, the name is taken from Vatican Hill, the geographic location of the state. Vatican is derived from the name of an Etruscan settlement, Vatica or Vaticum meaning garden, located in the area the Romans called vaticanus ager. The official Italian name of the city is Città del Vaticano or, more formally, Stato della Città del Vaticano, although the Holy See and the Catholic Church use Ecclesiastical Latin in official documents, the Vatican City officially uses Italian. The Latin name is Status Civitatis Vaticanæ, this is used in documents by not just the Holy See. The name Vatican was already in use in the time of the Roman Republic for an area on the west bank of the Tiber across from the city of Rome. Under the Roman Empire, many villas were constructed there, after Agrippina the Elder drained the area and laid out her gardens in the early 1st century AD. In AD40, her son, Emperor Caligula built in her gardens a circus for charioteers that was completed by Nero, the Circus Gaii et Neronis, usually called, simply. Even before the arrival of Christianity, it is supposed that this originally uninhabited part of Rome had long considered sacred. A shrine dedicated to the Phrygian goddess Cybele and her consort Attis remained active long after the Constantinian Basilica of St. Peter was built nearby, the particularly low quality of Vatican water, even after the reclamation of the area, was commented on by the poet Martial. The Vatican Obelisk was originally taken by Caligula from Heliopolis in Egypt to decorate the spina of his circus and is thus its last visible remnant and this area became the site of martyrdom of many Christians after the Great Fire of Rome in AD64. Ancient tradition holds that it was in this circus that Saint Peter was crucified upside-down, opposite the circus was a cemetery separated by the Via Cornelia. Peters in the first half of the 4th century, the Constantinian basilica was built in 326 over what was believed to be the tomb of Saint Peter, buried in that cemetery

9.
Mónaco
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Monaco, officially the Principality of Monaco, is a sovereign city-state and microstate, located on the French Riviera in Western Europe. France borders the country on three sides while the other side borders the Mediterranean Sea, Monaco has an area of 2.02 km2 and a population of about 38,400 according to the last census of 2015. With 19,009 inhabitants per km², it is the second smallest, Monaco has a land border of 5.47 km, a coastline of 3.83 km, and a width that varies between 1,700 and 349 m. The highest point in the country is a pathway named Chemin des Révoires on the slopes of Mont Agel, in the Les Révoires Ward. Monacos most populous Quartier is Monte Carlo and the most populous Ward is Larvotto/Bas Moulins, through land reclamation, Monacos land mass has expanded by twenty percent, in 2005, it had an area of only 1.974 km2. Monaco is known as a playground for the rich and famous, in 2014, it was noted about 30% of the population was made up of millionaires, more than in Zürich or Geneva. Monaco is a principality governed under a form of constitutional monarchy, although Prince Albert II is a constitutional monarch, he wields immense political power. The House of Grimaldi have ruled Monaco, with brief interruptions, the official language is French, but Monégasque, Italian, and English are widely spoken and understood. The states sovereignty was recognized by the Franco-Monegasque Treaty of 1861. Despite Monacos independence and separate foreign policy, its defense is the responsibility of France, however, Monaco does maintain two small military units. Economic development was spurred in the late 19th century with the opening of the countrys first casino, Monte Carlo, since then, Monacos mild climate, scenery, and gambling facilities have contributed to the principalitys status as a tourist destination and recreation center for the rich. In more recent years, Monaco has become a major banking center and has sought to diversify its economy into services and small, high-value-added, the state has no income tax, low business taxes, and is well known for being a tax haven. It is also the host of the street circuit motor race Monaco Grand Prix. Monaco is not formally a part of the European Union, but it participates in certain EU policies, including customs, through its relationship with France, Monaco uses the euro as its sole currency. Monaco joined the Council of Europe in 2004 and it is a member of the Organisation Internationale de la Francophonie. Monacos name comes from the nearby 6th-century BC Phocaean Greek colony, according to an ancient myth, Hercules passed through the Monaco area and turned away the previous gods. As a result, a temple was constructed there, the temple of Hercules Monoikos, because the only temple of this area was the House of Hercules, the city was called Monoikos. It ended up in the hands of the Holy Roman Empire, an ousted branch of a Genoese family, the Grimaldi, contested it for a hundred years before actually gaining control

10.
Isla Tromelin
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Tromelin Island is a low, flat, island in the Indian Ocean about 500 kilometers north of Réunion, and about 450 kilometres east of Madagascar. France and Mauritius have been negotiating for years in regard to a possible co-management of the island in the future and it also has a weather station and is a nesting site for boobies and green sea turtles. Tromelin Island has deep waters with a large fish resource, as Tromelin is only 7 metres high studies could not determine if it is the summit of a volcano or an atoll. Tromelin is about 1,700 metres long and 700 metres wide, with an area of 80 ha, covered in scrub dominated by octopus bush, there are no harbours or anchorages, so that access by sea is quite difficult. A1, 200-metre airstrip provides the link with the outside world. The island has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site. Both masked and red-footed boobies nesting there, sulidae populations have seriously declined in the western Indian Ocean with those on Tromelin among the healthiest remaining. The island’s masked boobies are of the western Indian Ocean subspecies, the red-footed boobies constitute the only polymorphic population in the region, indicating its biogeographical isolation. Both great and lesser frigatebirds used to nest on the island, the breeding populations of both birds have since been extirpated, although they continue to use the island for roosting. The island was discovered by France in 1722 and it was recorded by the French navigator Jean Marie Briand de la Feuillée and named Île des Sables. In 1761 the French ship Utile, carrying slaves from Madagascar to Mauritius, when the crew of the ship reached Madagascar they requested the colonial authorities to send a ship to rescue the people on the island. However, they met with a categorical refusal based on the fact that France was fighting the Seven Years War and no ship could be spared. Meanwhile, the people who had left on the bleak little island built a shed with coral stones. They also built a lookout on the highest point of the island in order not to miss the ship that would, they hoped and they were all from the Central Highlands and were not used to the marine environment. Most died within the first few months, fifteen years later in 1776, Bernard Boudin de Tromelin, captain of the French warship La Dauphine, visited the island and rescued the survivors — seven women and an eight-month-old child. The French claim to sovereignty dates from 29 November 1776, but Mauritius claims Tromelin, the United Nations never recognized the Mauritian sovereignty over Tromelin. In 1954, France constructed a station and a landing strip on the island. Indeed, as early as 1959, even before independence, Mauritius informed the World Meteorological Organization that it considered Tromelin to be part of its territory, France and Mauritius reached a co-management treaty in 2010