Before we start talking about the length of the circumference and the area of a circle, let's remember what each of the two is and why we can't use a single term to refer to the circle and circumference.
The circumference delimits the space filled by the circle.
THE circumferenceis a set of points that are the same distance from the center. This distance is known as lightning. THE circumference it is studied by Analytical Geometry and, in general, in a Cartesian plane. O circle, which is formed by the circumference and the infinite points that fill its interior, is studied by the Plane Geometry, as it occupies a space and can have its area calculated, unlike the circumference.
How to calculate the perimeter of a circle?
The perimeter is the measure of the outline of an object. In polygons, the perimeter is given from the sum of all its sides. In the circumference, the perimeter is obtained when we calculate its length.
To calculate the length of any circle, we need to know the measure of the
lightning (r). Knowing the radius value, the length of the circumference is given by twice the product of the radius by π (irrational number whose value approximate é 3,14). Be Ç O circumference length, we have the following formula:C = 2·π·r
If we multiply the radius of the circle by 2, we find the measure of the diameter (line segment that intersects two points on the circle passing through the center). Be d the diameter, we can also use the following formula to calculate the circumference length:
C = π·d
How to calculate the area of a circle?
As we said, the circle is a flat figure, so we can calculate its area. Unlike polygon bounded areas, we do not have a value for base or height measurements in a circle. Therefore, to calculate your area, we use the only information we have about you: the radius. THE area of a circle is given by the product of π and the square of the radius. Be THE the area of the circle, we have the following formula:
A = π·r²
If the circumference length is given in cm, the area of the circle will be given in cm²; if the circumference length is given in m, a circle area will be given in m² and so on.
By Amanda Gonçalves
Graduated in Mathematics
Source: Brazil School - https://brasilescola.uol.com.br/matematica/comprimento-area-circunferencia.htm
