The basic concept of 1. circle;
Circle: a figure consisting of a set of all points on a plane with equal distance from one point to another.
Center: the center point of a circle, represented by O.
Radius: the distance from the center of the circle to any point on the circle, expressed by R.
Diameter: The line segment passing through the center between two points is the two endpoints of the circle, and its length is 2r.
2. The nature of the circle:
The distance from any point on the circle to the center of the circle is equal.
The diameter of the circle is the longest diameter of the circle, and it is the two endpoints of the circle, and its length is 2r.
The radii of circles are equal.
A circle with equal radii.
The concept of pi indicates the ratio of circumference to diameter, which is usually expressed by pi, and the approximate value is 3. 14.
3. The circumference and area of the circle:
The circumference formula of a circle: C = π × diameter or C = 2 × π × radius.
The area formula of a circle: A = π × the square of radius.
4. The relationship between the circle and other graphics:
The relationship between a circle and right triangle, rectangle and other figures, such as calculating the circumference and area of a circle, may be related and compared with these figures.
5. The application of circle:
The application of circle in daily life and practical problems, such as the characteristics and application of circular objects such as tires, biscuits, clocks and watches.
When making mind maps, the above contents can be presented in the form of graphic combination. Basic concepts, properties, formulas, etc. You can explain the shape of the circle and mark the key points. At the same time, you can list keywords or related content on the edge or beside it to help deepen your understanding and memory. The typesetting of mind maps should be clear
Examples or questions can be added to the mind map, such as giving the diameter and radius of a circle and asking to calculate its perimeter and area; Or put forward some practical application scenarios, such as the shape of biscuits and the characteristics of wheels, so that students can understand and apply the relevant knowledge of circles through thinking and calculation.