Proportion – the widespread term which is used in many areas of human activity, including mathematics, physics, chemistry, medicine, drawing, architecture, etc.
The proportion (Latin of proportio - "ratio") is the relation between two or more proportional sizes. The term "proportion" is used in mathematics, architecture, medicine and other fields of science and art. The proportion in mathematics is an equality between the relations of four proportional sizes, i.e. equality of a type of a: b = c: d. It is possible to read this ratio as follows: "size a belongs to size b the same as c belongs to d". an and d call extremes of a proportion, and b and c – averages. If to rewrite equality in the form of the work, then it will turn out that the work by her average members is equal to the work of extreme: b*c = a*d. From a mathematical definition of a proportion the term "golden ratio" which is widely used in science follows. In architecture, painting and medicine it is connected with appeal of human or subject lines. The golden ratio is called still a harmonious proportion. At golden ratio a certain size is divided into two parts so that a smaller part belonged to bigger the same as big belongs to all size. For the first time this method was described by Euclid in the 3rd century BC. And famous Leonardo Da Vinci the first began to use golden ratio consciously in creation of the masterpieces. It is considered that during creation of pyramids, temples, tombs and other antique buildings, the method of golden ratio was used. However actually use of this term in architecture and art only means that asymmetric proportions which not necessarily submit to the rule of golden ratio mathematically were used. Approximately at the end of the 15th century Da Vinci created the well-known drawing "Vitruviansky Person" in which he represented proportions of a human body. This drawing was an illustration to descriptions of the human proportions created by the antique architect Vitruvius and became a symbol of symmetry of a human body in painting. In medicine various types of proportions of a body depending on age, growth, a floor and type of a constitution of the person are used. The concept of a proportion is applied when mixing liquid substances. For example, in chemistry or pharmaceutics and also in cookery at preparation of dishes.