Solid geometry should do more questions, and cultivate your spatial imagination ability in the questions. Geometry topics should be drawn by themselves, in fact, it is to express their spatial imagination in the process of drawing by themselves. Then when doing the problem, all the problems are solved by geometric methods, instead of establishing rectangular coordinate system. The method of establishing coordinate system is very simple, without thinking, but it is not good for you to do the problem like this, so you must use geometric methods to solve it, and finally you will feel it. At this time, your spatial imagination will be cultivated. Once mastered, solid geometry will be particularly simple.

Let me give you a summary: the favorite topic of solid geometry is nothing more than:

(1) positional relationship between straight lines: This kind of problem mainly examines straight lines on different planes, and the key to solving the problem of straight lines on different planes is to transfer straight lines on different planes to the same plane as much as possible. To put it bluntly, this is to find a parallel plane and transfer it to a plane, and the rest is the knowledge of plane geometry. You should be fine. Just practice more.

(2) Relationship between lines and surfaces: Lines and surfaces are nothing more than the distance between points and surfaces, and the positional relationship between lines and surfaces, that is, whether they are vertical or not. Stick to a theorem (a straight line outside the plane is perpendicular to any two intersecting lines in the plane, then this straight line is perpendicular to this plane), and you will know how to do the problem if you firmly grasp this theorem.

(3) Relationship between faces: The focus of this test is dihedral angle, which is the key point. It is suggested to find the dihedral angle by graphic method (three steps, the first step is to find the common straight line of two planes, then find the straight line perpendicular to the common straight line in two planes, and finally translate it to one plane, so the dihedral angle is the dihedral angle).

In short, solid geometry is to practice more and try various methods to solve problems. If you persist, I believe you will find solid geometry very simple.

If you have any questions or questions, you can ask me. I still have some experience in high school mathematics.