The circle is a geometric figure delimited by a circumference. Therefore, the circumference is the curved line that forms the limit of the figure, and the circle is the area that contains the circumference.
Parts of the circle
The main elements of the circle are:
- Circumference: Curved line that forms the limit of the circle.
- Center: It is the midpoint of the circle or center of the circumference.
- Radius: The line joins the center with any point of the circumference.
- Diameter: Straight line that joins two circumference points, passing through the center. The diameter equals twice the radius. In other words, the radius is half the diameter.
Area of a circle
The area of a circle is calculated using the formula:
Area = πr2
Where:
- r corresponds to the radius.
- π is the number pi = 3.1415
Perimeter or circumference of a circle
The perimeter of a circle is the measure of its circumference. Knowing the radius, it is possible to calculate the perimeter using the formula:
Perimeter = 2πr
Where:
- r corresponds to the radius.
- π is the number pi = 3.1415…
