1. Definition: The corresponding angles of similar figures are equal, and the corresponding edges are proportional.
2. Find the scale factor: Find the scale factor between two graphs, that is, the length ratio of the corresponding edges. Two graphs are similar if the length ratio of their corresponding edges is equal.
3. Determine the equivalence relation: Determine the equivalence relation between two graphs, that is, the distance ratio between corresponding points. Two graphs are similar if the distance ratio between their corresponding points is equal.
4. Visual graphics: Prove the similarity between two graphics through visual graphics, such as judging whether two graphics are similar by measuring the characteristics such as angle and length.
5. Check features: Check how many features are the same between two drawings, such as lines, angles, arcs and arcs. Two graphs are similar if they have the same number of features and the shapes and sizes of these features are the same.
6. Application Theorem: Prove the similarity of two graphs with relevant theorems, such as the proportion theorem of parallel lines and the similarity theorem of parallel triangles.
Proof questions need to pay attention to the following points:
1, specifying the known conditions and conclusions. Before solving a problem, you need to read the topic carefully and make clear the known conditions and conclusions, so as to determine the direction and thinking of solving the problem.
2. Determine the ideas and methods of proof. According to the known conditions and conclusions, we can determine the ideas and methods of proof through analysis, induction and reasoning, but we need to pay attention to the rigor and consistency of logic.
3. Pay attention to language expression and the use of symbols. When solving problems, we need to pay attention to the implicit conditions in the topic, such as the properties and inequalities of some geometric figures, to avoid mistakes and omissions.
4. Consider various solutions. When solving problems, we need to consider a variety of solutions, so as to better understand the topic and problem-solving ideas, and also provide reference and enlightenment for subsequent problem-solving.
5. Summarize experience and skills. After solving problems, it is necessary to sum up experience and skills, so as to better master the methods and skills of solving problems and improve the ability and level of solving problems.