One needs to know just the radius or the diameter of a circle in order to calculate its circumference. If by moving the measurement instrument slightly you get a bigger diameter size, then go with that.Įxample: find the circumference of a circle To make sure you are measuring the diameter correctly, it should be the biggest measurement you can get.
CIRCLE CALCULATOR HOW TO
How to calculate the circumference of a circle?Ĭalculation is easy once you have measured the circle's radius or diameter, using the formulas above or, if you prefer the easier way - using our circumference of a circle calculator above. The calculation result is in the unit in which you measured the circle radius or diameter. If you know the diameter, it is 2 times the radius, so just divide by two, to get the radius, or use this formula: π x diameter. In practical situations it is often easier to measure the diameter instead of the radius. It was originally defined as the ratio of a circle's circumference to its diameter (see second formula below on why) and appears in many formulas in mathematics, physics, and everyday life. The circumference of a circle is calculated using the formula: 2 x π x radius, where π is a mathematical constant, equal to about 3.14159. Example: find the circumference of a circle.How to calculate the circumference of a circle?.The area of a circle can be also described as the number of square units needed to cover the surface of a disk surrounded by a circle. In many other languages, there is no such ambiguity. We will start by stating the interesting fact that in the English language the area of a disk is somewhat incorrectly called the area of a circle, which is actually the area of a line or a curve (yes, a circle is a curve!) and a line or a curve has no area!Ī disk, which is a round portion of a plane with a circular outline has an area A defined as π R squared:Īnd this area of a disk is more often called the area of a circle. It is interesting to note that since the exact value of π cannot be calculated, it is impossible to find the exact circumference or area of a circle. For example, √2 is irrational, but not transcendental because it is a root of the equation x² - 2 = 0. There are common numbers that are irrational, but not transcendental. This means it cannot be represented exactly by a common fraction and it is not the root of any polynomial with rational coefficients. π is an irrational and transcendental number. Though this number is known from antiquity, it has been represented by the Greek letter π recently - since the mid-18 century. The mathematical constant π is widely used in many formulas in mathematics, engineering, science and architecture, and construction. Rearranging the above formula, we can solve it for the circumference and get the formula everyone remembers from school: If we divide the circumference of any circle by its diameter D, we get the number 3.14159265359… This number is the most important mathematical constant called π: The circumference C of a circle is the length of the perimeter of a circle, that is, the length of the circle or the distance around the circle. To be more exact, a circle is a line or a closed curve and in strict language, the circle is only the line that encloses the figure called a disk in American English or disc in British English.
Any diameter divides the circle (or rather the disk) into two equal halves. The diameter equals twice the radius of the circle. In more exact words, it is the segment of a straight line that passes through the center of the circle and ends where it touches two points on the circle. The diameter of a circle is the distance across the circle. In some metric spaces, for example in the taxicab or Chebyshev’s spaces the circles look rather square. However, a circle looks round only in Euclidean geometry. We used to view a circle as a round line or figure. The distance from any point of the circle to its center is called the radius. Coplanar points are points located in a plane. In other words, a circle is a locus of coplanar points equidistant from a certain point called the center. In geometry, a circle is a set of all points in a plane that have the same distance to a point called the center of the circle. Circles in Agriculture Definitions and Formulas