Brief introduction of formula

The content of the formula is the square of pi * radius, which can be expressed in letters as: S=πr? Or S=π*(d/2)? . (π stands for π(3. 14 15926 ...), r stands for radius and d stands for diameter).

Source of formula

Kepler is a German astronomer, physicist and mathematician, and the founder of modern experimental optics. He used to be a math teacher and was very interested in finding the area. He made an in-depth study.

He thought that ancient mathematicians used division to find the area of a circle, and the results were approximate. In order to improve the approximation, they constantly increase the number of segmentation. But no matter how many times it is divided, as long as it is limited, it will always get an approximate value of the circular area. In order to get the accurate value of the circle area, it is necessary to divide the circle into an infinite number of equal parts.

Kepler boldly divided the circle into infinitely many small sectors by infinite division, and boldly asserted that the area of an infinitesimal sector is equal to the area of its corresponding infinitesimal triangle. He took an important step forward on the basis of calculating the circle area before.

16 15 years, he published this new method of finding the circular area created by himself in his book "Solid Geometry of Barrels". Mathematicians spoke highly of Kepler's work and praised this book as an inspiration for people to create new methods to find the area and volume of a circle.