How to calculate the circumference of thick plate winding

The calculation formula of coiling circumference of thick plate is: circumference = diameter of circle (R)×(π) diameter. The circumference of a circle is a mathematical phenomenon that the N-polygon is inscribed in a circle, the side length is set to an, and the circumference of a regular N-polygon is n×an. When n is increasing, the perimeter of regular polygon approaches the perimeter of circle C, that is, n approaches infinity, and C=n×an.

A circle is a geometric figure. By definition, compasses are usually used to draw circles. The diameter and radius of the inner circle of the same circle are always the same, and the circle has countless radii and diameters. A circle is a figure with axial symmetry and central symmetry. The axis of symmetry is the straight line where the diameter lies. At the same time, the circle is a "positive infinite polygon" and "infinity" is just a concept. The more sides a polygon has, the closer its shape, perimeter and area are to a circle. So there is no real circle in the world, and the circle is actually just a conceptual figure.