First, the cultivation and stimulation of interest * As the saying goes, "Geometry begins with algebra", and the introduction to geometric proof is rather boring, so cultivating interest in learning is the prerequisite for success. Einstein, a master of modern physics, famously said that "interest is the best teacher", which can induce and strengthen learning motivation. Judging from the psychological state of junior high school students, their learning activities are most likely to start from interest and are also most likely to be influenced by interest. In the interesting learning activities, their thinking is the most active and their intelligence and ability are also fully developed. Therefore, in the teaching process, we should fully combine the reality and cultivate their interest in learning.

(1) Stimulate students' interest in learning with examples in life. Vivid scenes in life are rich teaching materials and curriculum resources. These materials can stimulate students' interest in mathematics, enhance their feelings about mathematics, and help students understand abstract mathematical logic and concepts. Because geometric figures have many applications in real life, in view of this feature, let students review the examples of geometric figures in real life before teaching. For example, how to fix a piece of wood on the wall, students will definitely answer how to nail two nails (two points determine a straight line), how to fix a swinging quadrilateral (with the help of the stability of a triangle), the principle of pulling a switch (the instability of a quadrilateral), architectural design, interior decoration, highway intersection design, pattern design (these mainly use graphic translation, axial symmetry and rotation) and so on. Let students fully realize the usefulness of learning before learning and stimulate students' interest in learning.

(2) Stimulate learning interest through activities * The new curriculum standard points out that mathematics teaching is the teaching of teaching activities and the process of communication, interaction and common development between teachers and students. Effective mathematics teaching should start from students' life experience and existing knowledge background, and provide them with sufficient opportunities to engage in teaching activities. "Activity teaching" is an effective means of junior high school mathematics teaching. Using activities to explore and learn abstract knowledge can effectively stimulate junior high school students' interest in learning, improve their enthusiasm for thinking, and make them learn mathematics easily and happily in a happy mood. Psychologist Bruner believes that learning is an active process, and the best motivation for students to learn is to arouse their interest in the materials they have learned, that is, the intrinsic motivation from the learning activity itself, which is the psychological motivation that directly promotes students' active learning. Therefore, in the teaching process, we should make use of the contents of textbooks and seize every opportunity to let students start work. For example, in the teaching of congruent triangles, students can draw a triangle according to the known conditions, then cut it out and compare it to see if it coincides or compare it with other students. This will enable students to learn how to judge congruence in activities. When explaining how to solve practical problems with trigonometric function, students can measure the height of flagpole on the playground with goniometer.