The circumference of a circle can be calculated by the formula C=πd or C=2πr, where π represents pi, d represents the diameter of the circle and r represents the radius of the circle.

That is, the circumference of a circle is π times the diameter or 2π times the radius.

It should be noted that pi is an irrational number and cannot be expressed by the ratio of two integers, and its value is about 3. 14 159. When calculating, we usually use approximate values to calculate.

Circumference is an ancient and important mathematical concept, and its calculation method is also a very basic and important mathematical formula. The calculation method of the circumference of a circle will be expanded and explained in more detail below.

The Origin and Definition of Pi

π π originated from the study of circles by ancient mathematicians. Archimedes, an ancient Greek mathematician, gave an approximate value of pi for the first time in the book Measurement of Circle, while Zu Chongzhi, a mathematician in the Northern and Southern Dynasties of China, made pi accurate to seven decimal places for the first time.

Pi is an irrational number, which cannot be expressed as the ratio of two integers, and its value is about 3. 14 159. Pi is widely used, including geometry, astronomy, engineering and other fields.

Approximation and rounding method of pi

In practical application, we usually use the approximate value of pi to calculate. Commonly used approximations are 3. 14, 3. 14 159, 3. 14 15926, etc. In the field of scientific research and engineering, higher precision and rounding method are needed to meet the actual needs.

Practical application of circle circumference calculation

Circumference is widely used in many fields. For example, in mechanical engineering, the circumference can be used to calculate the lateral area and surface area of a cylinder; In physics, the circle can be used to calculate the trajectory of particle motion; In earth science, the circumference can be used to calculate the circumference of the earth and measure the latitude and longitude.