The construction mode of mathematical mind map is to first determine the central theme, lead out the sub-themes, and then divide the sub-themes into different levels. The specific operation steps are as follows. 1. Use the simplest language to determine the mathematical theme to be drawn. Take "angle measurement" as an example, as shown in the figure below. 2. The angle is a graph composed of two rays drawn from a point, so start with the ray. 3. Draw line segments and straight lines with rays and compare their similarities and differences. As shown in the figure below. 4. Mark the angle of key knowledge points on the mind map. As shown in the figure below.

Note: In the mind map above, the definition of light is derived from the angle. Draw a line between the angle and the ray, so that we can connect the knowledge points in series.