Circumference of a circle

To calculate the circumference of a circle, all you need to know is:

- diameter,

- radius,

- area of ​​a circle,

- the diagonal of the inscribed rectangle,

- the side of the circumscribed square,

- sides and area of an inscribed triangle,

are the area and half-perimeter of the circumscribed triangle,

side of an inscribed regular polygon.

The purpose of this application is the education of cognitive interest in mathematics.