1, right angle: An angle equal to 90 degrees is called a right angle. It has a very obvious feature that its two sides are perpendicular to each other. In real life, we often see right angles, such as corners, doors and windows.
2. Acute angle: An angle less than 90 degrees is called acute angle. An acute angle looks sharp, and its degree is less than a right angle. Imagine if we fold one side of a right angle inward, then an acute angle will be formed.
3. Oblique angle: An angle greater than 90 degrees and less than 180 degrees is called an obtuse angle. The obtuse angle looks "blunt", and its degree is greater than the right angle but less than the right angle. Imagine if we fold one side of the right angle outward, it will form an obtuse angle.
When learning these angles, students usually use tools such as triangle and protractor to measure and compare them. At the same time, they will also learn how to use the properties of these angles to solve some practical problems, such as calculating angles and judging the shape of graphics.
How to master right angle, acute angle and obtuse angle quickly in the second grade of primary school;
1. Understanding concepts: First, you need to understand the basic concepts of right angle, acute angle and obtuse angle. These concepts can be explained by simple language and diagrams, such as folding a piece of paper into different angles to show the characteristics of these angles.
2. Comparative memory: Compare right angles, acute angles and obtuse angles to find out their similarities and differences. For example, we can compare their degrees and whether they are vertical.
3. Practical operation: Let students do it themselves, such as folding paper and splicing with sticks, and actually feel the characteristics of different types of corners.
4. Classification and induction: classify and induce different types of angles and summarize their similarities and differences. For example, we can compare the degree range and verticality of right angle, acute angle and obtuse angle.
5. Repeated practice: deepen the understanding and memory of the concepts of right angle, acute angle and obtuse angle through repeated practice. For example, you can take a quiz in class, or let students practice by themselves after class.
6. Combining life: Combining mathematics knowledge with daily life, let students feel the application of right angle, acute angle and obtuse angle in real life.