Is the middle of a circle, that is, the area between a square and a circle (square and inscribed circle) 9(d/3)? -7(d/3)？ =2(d/3)？ . The circle in a square, that is, the area between the circle and the square (circle and inscribed square) is 7(d/3)? -4.5(d/3)？ =2.5(d/3)？ .
Is the area between a square and a square (circumscribed circle and inscribed circle of a circle) 9(d/3)? -4.5(d/3)？ =4.5(d/3)？ .
By dividing the China side of a circle into two triangles, we can find out the area of the China side of the circle. First draw a circle according to the description of the topic, and draw a square in the middle of the circle. Connect the squares in the circle diagonally and divide them into two equal equilateral right triangles. The sum of the areas of two triangles can get the area of a circle. The diameter of the circle is the base of the triangle, and the radius of the circle is the height of the triangle.
Introduction to mathematics:
Mathematics is a discipline that studies the concepts of quantity, structure, change, space and information, and belongs to a formal science from a certain point of view. Ancient mathematics in China was called arithmetic, also called arithmetic, and was finally changed to mathematics. Arithmetic in ancient China was one of the six arts.
Mathematics is produced by counting, calculating, measuring and observing the shape and motion of objects through abstract and logical reasoning. [1] Mathematics has become a part of education in many countries and regions. It is applied in different fields, including science, engineering, medicine, economy and finance. Mathematicians also study pure mathematics, which is the substantive content of mathematics itself and does not aim at any practical application.