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| units3 = degrees | inunits3 = ° }} The gradian is a unit of measurement of an angle, equivalent to of a turn, of a degree or of a radian. It is also known as gon (from Greek ''γωνία''/''gōnía'' for angle), grad, or grade. In continental Europe, the French term ''centigrade'' was in use for one hundredth of a grad. This was one reason for the adoption of the term Celsius to replace centigrade as the name of the temperature scale.〔. On (p. 42 ) Frasier argues for using grads instead of radians as a standard unit of angle, but for renaming grads to "radials" instead of renaming the temperature scale.〕 == History == The unit originated in France as the ''grade'', along with the metric system, hence it is occasionally referred to a "metric degree". Due to confusion with existing ''grad(e)'' units of northern Europe, the name ''gon'' was later adopted, first in those regions, later as the international standard. In German, the unit was formerly also called ''Neugrad'' (new degree), likewise ''Nygrad'' in Swedish, Danish and Norwegian (also ''Gradian''), and ''Nýgráða'' in Icelandic. Although attempts at a general introduction were made, the unit was only adopted in some countries and for specialised areas such as surveying, mining and geology. The French artillery has used the grad for decades. The degree, of a circle, or the mathematically more convenient radian, of a circle (used in the SI system of units) are generally used instead. In the 1970s and 1980s most any scientific calculators offered the grad as well as radians and degrees for their trigonometric functions In the 2010s some scientific calculators lack support for gradians. The international standard symbol for this unit today is "gon" (see ISO 31-1). Other symbols used in the past include "gr", "grd", and "g", the last sometimes written as a superscript, similarly to a degree sign: 50g = 45°. "Grad" was commonly used on calculators with LCD displays, as "DEG", "GRAD", and "RAD" could all be represented as a subsection of a three-segment panel forming the string of letters "DEGRAD". 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gradian」の詳細全文を読む スポンサード リンク
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