First of all, there must be a format, first (proof:) and then write the process. Process: Because there is XX (condition), there is XX (conclusion) to write. This is the format. Because there is sum, there are special symbols in mathematics to replace it. According to the process of solving, you need to use a pencil to make auxiliary lines on the diagram, usually dotted lines. The whole idea of doing geometric problems is to deduce conclusions from conditions, that is, to deduce the conclusions needed by the problem step by step according to the conditions given by the title and some characteristics of geometric figures. For example, when you see the parallel lines in the picture, you will think of several parallel line theorems, and then you can use the parallel line theorems to find another unknown angle according to the known angle given by the topic. This idea of seeking the unknown from the known can also be applied to other mathematical problems. In the third grade, you may learn the unknown and infer the known. Actually, the principle is similar. Learn the basics first. The key to doing geometry problems is to be familiar with theorems and formulas, so that you can think of corresponding theorems when you look at the problems. At ordinary times, we should train ourselves to do problems without reading books and form good habits.