How to make a circular handwritten newspaper?

The methods of handwritten newspaper are: circle introduction, circle diagram, history introduction and pi.

Introduction to the circle

In a plane, a closed curve formed by rotating around a point for a certain length is called a circle. On the plane, a circle is a set of points whose distance from a fixed point is equal to a fixed length. A circle has countless axes of symmetry, which pass through the center of the circle. A circle has rotation invariance. A circle is a conic curve, which is obtained by cutting a cone from a plane parallel to the bottom of the cone.

Second, circular graphics.

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.

A circle can be regarded as a regular polygon composed of countless infinitesimal points. 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.

Three. Introduction to history

A circle is a seemingly simple shape, but in fact it is very wonderful. The ancients first got the concept of circle from the sun and the moon on the fifteenth day of the lunar calendar. On the Neanderthal 18000 years ago, he used to drill holes in animal teeth, gravel and stone beads, some of which were very round. In the pottery age, many pottery were round. Round pottery is made by putting clay on a turntable.

When people start spinning, they make round stone spindles or ceramic spindles. The ancients also found it easier to roll when carrying logs. Later, when they were carrying heavy objects, they put some logs under big trees and stones and rolled them around, which was of course much more labor-saving than carrying them.

Fourth, pi

The ratio of the circumference to the diameter of any circle is a fixed number, called pi, which is expressed by the letter π. It is an infinite acyclic decimal, π = 3. 14 15926535 ... but in practical application, it is generally only an approximation, that is, π≈3. 14. If the circumference of a circle is represented by c: C=πd or c = 2 π r.