The handwritten report of the circle is as follows:

1. Historical introduction of the circle:

The circle is a seemingly simple but actually very wonderful shape. Ancient people first got the concept of circle from the sun and the moon on the fifteenth day of the lunar calendar. In the caveman 18, years ago, he used to drill holes in animal teeth, gravel and stone beads, and some of those holes were very round. In the pottery age, many pottery were round. Round pottery is made by putting clay on a turntable.

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

Second, the definition of a circle:

1. The set of points whose distance from a fixed point in the same plane is equal to a fixed length is called a circle. This fixed point is called the center of a circle.

2. The length of a circle is the circumference of the circle. Two circles that can completely coincide are called equal circles.

3. A circle is not a regular N-polygon (n is an infinite positive integer). A regular N-polygon whose side length is infinitely close to but can never be equal to can be approximately equal to a circle, but it is not a circle.

application of the circle:

1. Physics: In physics, the circle is a basic mathematical tool, which can be used to describe and calculate various phenomena and problems, such as electronic orbits, optical devices and mechanical parts.

2. Engineering: In engineering, circle is a very useful mathematical tool, which can be used to describe and calculate various phenomena and problems, such as the running track of mechanical parts and the design of building structures.

3. Computer science: In computer science, a circle is a basic graphic shape, which can be used to create various graphics and animation effects, such as drawing circles and spheres.

4. Earth science: In earth science, circles are also widely used, such as describing the shape and size of the earth in geography and the path of storms in meteorology.

5. Medicine: In the medical field, circles also have many applications. For example, in medical imaging, circular scanning areas are often used to examine the morphology and structure of organs and tissues.