The calculation of regular polygon in junior high school mathematics: the perimeter of regular polygon is equal to the sum of the sides.

Regular polygons are introduced as follows

A regular polygon refers to a polygon with equal sides and angles in a two-dimensional plane, also called a regular polygon. Polygons with equal sides and angles are called regular polygons. The center of the circumscribed circle of a regular polygon is called the center of a regular polygon. The radius of the circumscribed circle of a regular polygon is called the radius of a regular polygon. The distance from the center to the edge of a regular polygon inscribed in a circle is called apogee.

The ruler method for drawing regular polygons is introduced as follows:

Rulers, compasses and protractors can draw any regular polygon. But in ancient Greece, only unmarked rulers and compasses were used for drawing. It is not difficult to make 2n, 3×2n, 5×2n equilateral regular polygons with a ruler.

However, it is difficult to draw regular odd edges, such as 3, 5, 7, 9, 1 1 3, 15, and not all edges can be drawn. 1798, German mathematician Gauss was 19 years old. He succeeded in making a regular heptagon with compasses. 180 1 year, the mathematician Gauss proved that if fermat number k is a prime number, then the perimeter k can be divided equally with a ruler and compass.

However, Gauss himself can't actually make a regular heptagon. The first real drawing method of regular heptagon ruler was Johannes Erchinger) until 1825), and it was proved that the number of sides of regular polygons can only be drawn with a ruler when they are Fermat prime numbers or products of different Fermat prime numbers.

Polygons are introduced as follows:

In mathematics, a plane figure consisting of three or more line segments connected end to end is called a polygon. According to different standards, polygons can be divided into regular polygons and irregular polygons, convex polygons and concave polygons. A closed figure composed of three or more line segments on the same plane but not on the same straight line, which is connected end to end and does not intersect, is called a polygon.