1, perimeter formula: C=2πr, where r is the radius. The circumference of a circle is equal to π times the diameter, where π is an irrational number, which is approximately equal to 3. 14 15926.

2. Formula of circular area: S=πr? Where r is the radius. The area of a circle is equal to π times the square of radius.

3. Formula of circle volume: V=4/3πR? Where r is the radius. The volume of a circle is equal to 4/3 times π times the cube of radius.

4. Formula of circular surface area: S=4πR? Where r is the radius. The surface area of a circle is equal to 4 times π times the square of the radius.

A circle is a geometric figure surrounded by a curve, which is defined as a set of points whose distance from a fixed point (f) is equal to a fixed length (r). Circle is ubiquitous in life and widely used in architecture, machinery, electronics, transportation, art and other fields. The basic properties of a circle include: the radius length is equal, the distance from the center of the circle to the circle is equal, and the diameter is twice the radius.

The formulas for calculating the circumference and area of a circle are C=2πr and S=πr? Where r is the radius. Through the radius or diameter of the circle, the area, perimeter, sphere volume and sphere surface area of the circle can also be calculated.

Advantages of learning mathematics

People who are good at math are relatively smart and savvy, and they can show their advantages in dealing with people. The faster you think, the more ways and ideas you have. Mathematics is the foundation of other disciplines, and it is easier for people who learn mathematics well to get into other disciplines. Learning software, computer, finance and other engineering majors is even more handy.

It is used everywhere in life. Nowadays, the society is an information society, and mathematical knowledge is used in financial management and computers. Mathematics can cultivate people's integrity and honesty. Mathematics pays the most attention to convincing people by reasoning, and only believes in the results of logical reasoning. Mathematics can cultivate people's tenacity and courage. Mathematics can cultivate people's overall consciousness. Mathematics can cultivate people's good character.