First, the cylinder (cone) problem. Know the bottom, side and height of a cylinder; Know the bottom and height of the cone. If you want to know the unfolded figure of the cylinder's side, know the calculation method of the lateral area and surface area of the cylinder, you can calculate the lateral area and surface area of the cylinder, use the calculation method flexibly according to the actual situation, and know the approximate method.
Second, the problem of area and volume. Mainly consider the following contents: How to get the calculation formula of parallelogram area? How to calculate the area of triangle and trapezoid? What about the formula for calculating the area of a circle? Think about how the square area is calculated. Why? What is the surface area of three-dimensional graphics? How to calculate the surface area of a cuboid? Is there any simple way to solve this kind of problem? How to calculate the surface area of a cylinder? What are the similarities between a cuboid and a cylinder?
Third, statistics. Simple statistical tables, charts, and learning to calculate averages and percentages are all preliminary knowledge of statistics. In statistical work, in addition to sorting data, it can also be represented by statistical tables, and sometimes it can also be represented by statistical charts. There are three kinds of common statistical charts: bar statistical charts; Broken line statistical chart; Department statistical chart. To understand the statistical chart and clarify its characteristics and functions, it is necessary to go through the process of collecting and sorting out data, representing data with statistical charts and sorting out results. According to the statistical chart drawn, we can analyze some simple facts reflected by the data, make some simple reasoning and judgment, and further understand that statistics is a strategy and method to solve practical problems. In the junior high school exam, many students are prone to lose points on the above knowledge points, so I hope students can pay attention to these knowledge points when reviewing to avoid mistakes in the exam.