1. Use rope or belt: wrap the rope or belt tightly around the circumference, and mark both ends of the rope or belt with a marker pen or scissors. Then unfold the rope or belt and measure the distance between the two marks, which is the circumference of the circle.

2. Use the scale: aim one end of the scale at the starting point of the circle, then place the scale along the circle and move along the circle until the other end of the scale returns to the starting point again. Read the length of the ruler and multiply it by π (pi). This product is the circumference of the circle.

3. Using Angle and Radius: Measure the radius of the circle, and then multiply it by 2π(π) to get the circumference of the circle. In addition, the formulas of angle and radius can be used to calculate the circumference of a circle. That is, the circumference =2πr×(θ/360), where R is the radius and θ is the degree of the central angle. The central angle is the angle with the vertex as the center and the two sides tangent to the circumference respectively.

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.