Compile directly, enter any radius r in the program output result, and the program execution result is shown in the following figure:
Extended data:
The circumference of a circle is a mathematical phenomenon that the n-polygon is inscribed in a circle, the side length is set to an, and the circumference of a regular n-polygon is n*an. When n is increasing, the perimeter of a regular polygon approaches the perimeter of a circle, that is, n approaches infinity, and C=n*an.
The formula of circular area is a theorem. Is the square of pi * radius, which can be expressed in letters as: S=πr? Or S=π*(d/2)? . (π stands for pi, r stands for radius and d stands for diameter).
Pi is the ratio of the circumference to the diameter of a circle, which is generally expressed by the Greek letter π and is a universal mathematical constant in mathematics and physics. π is also equal to the ratio of the area of a circle to the square of its radius. Accurate calculation of geometric shapes such as circle perimeter, circle area and sphere volume is the key value.
The full text is 4700 words and the reading time is about 6 minutes.
The writer is the dean and professor of the Institute of Educational Sciences of Hangzhou Normal Un