The area and the circumference of circle is calculated from the radius using the formula.
When the radius r is input and "Calculate area of circle" button is clicked, the area and the circumference of the circle are calculated and displayed.
![Area of a circle](/img/area_en/circle.png)
![Formula of area of circle](/img/area_en/circle1.jpg)
![Formula of circumference of circle](/img/area_en/circle2.jpg)
The area of the circle where the radius is 1
Area S: 3.1415926535898
Perimeter L: 6.2831853071796
Perimeter L: 6.2831853071796