# What is the diameter of a circle

Before considering the diameter of a circle, let's talk about its length. By this term is meant the product of the diameter by the number "pi". For example, for a given radius of a circle, you can determine not only the length, but also calculate its area. For any species, the constant value is a fraction, in which the numerator is length, and the denominator is the diameter of a circle.

## Definition

For all round geometric shapes, the ratio of length to diameter will be the same. For example, knowing the magnitude of the radius of a round figure, it is quite possible to find its length, diameter, and area. The length of the circle is the product of the number "πi" and the diameter of the circle.

Such a value is considered in the geometry of the curved line bounding the circle. Since the figures are represented on a plane, such a definition characterizes a two-dimensional image. The points of the considered curve at the same distance are removed from the center of the selected circle.

## Calculations

Knowing what is the radius of our planet, it is easy to determine the length of the circular orbit of the satellite of the Earth.In practice, such calculations are rarely carried out, since the number “pi” is approximate, therefore the probability of error is high. In order to determine its length in everyday life through the diameter of a circle, a device such as a curvimeter is used.

## Application and formula

Knowing the diameter of the circle, you can carry out the construction of residential buildings, entertainment centers, supermarkets. Design engineers engaged in the development of a variety of machines, units, mechanisms, are constantly faced with similar calculations. What is the formula for the diameter of this curve? Draw it with compasses. In mathematics, the method of indirect calculation of the circumference is used.

The easiest way is to use a radius. The diameter is calculated as two radii. For a given circumference of a circle, its diameter can be determined by dividing the length by the number "pi". For example, with a length of 10 centimeters diameter will be 10: 3.14 = 3.18 centimeters.

For a given area of a circle, the diameter is calculated by taking the square root of a given number, then dividing the response by the number "pi".For example, if the area of a circle is 25 square centimeters, the square root will be 5 centimeters, and after dividing this number by 3.14, we get 1.59 cm. This is the diameter of a circle given in the problem.

To cope with such simple calculations can and ordinary student of the school, and the engineer of the design office.