Generally speaking, this junior high school math class is very successful in evaluating the relationship between the angle of a circle and the angle of the center of the circle.

First of all, from the definition, the teacher clearly explains the concepts of central angle and circumferential angle, so that students can have a clear understanding of these two concepts. In particular, the central angle, the teacher through physical display and examples, let the students understand that the central angle is the angle with the vertex at the center of the circle.

Secondly, when talking about the relationship between the central angle and the outer angle, the teacher used a very vivid way. By rotating the central angle, he lets students observe the relationship between the central angle and the arc and string it faces. In this way, students can easily understand the equivalent relationship between the central angle and the arc and chord it subtends, and the application of these relationships in proof and calculation.

In addition, teachers also pay attention to the cultivation of students' thinking ability in class. He asked, "If the central angle of an arc is 90 degrees, what is the chord of this arc?"

Through thinking and practice, students can deduce that if one of the distances between the centers of two central angles, two external angles, two sets of arcs, two chords and two chords is equal in the same circle or the same circle, the corresponding other set of quantities are equal respectively. This way not only allows students to better understand knowledge points, but also exercises their thinking ability.

Finally, at the end of the course, the teacher briefly introduced the application of central angle and circumferential angle, so that students can understand the application of these two concepts in real life, thus stimulating their interest in mathematics learning.

Generally speaking, this junior high school math class is very successful in evaluating the relationship between the angle of a circle and the angle of the center of the circle. The teacher clearly explained the concept, vividly displayed the relationship, paid attention to the training of students' thinking ability, and also stimulated students' interest in learning. This is a very in-depth and extensive math class, which is of great help to improve students' math literacy.