As the name implies, protractor is an instrument used to measure the degree of angle, which can measure angle, inclination, verticality and levelness. In addition, the protractor is also a drawing tool, which can draw angles, vertical lines and parallel lines, can be opened and closed as an inner and outer square ruler, and can be used as a length ruler, so that the reading is more accurate and intuitive, and a circle inch with a specified size can be drawn. The common material of protractor is plastic or iron, and it is often used with compasses.
Second, how to use the protractor
(1) Measure the degree of angle.
1, protractor is a tool used to measure the degree of an angle, which is generally semicircular.
2. The diameter of the semicircle is the zero scale line of the protractor, and the center of the diameter is the center of the protractor.
3. The scale on the semicircle is used to measure the degree of angle, ranging from 0 to 180 degrees.
4. When measuring the angle, first put the protractor on the drawn angle, then find the vertex of the angle, so that the center position of the protractor coincides with the vertex of the angle, and then one side of the angle coincides with the zero scale line.
5. After completing the two coincidences, you can measure the degree of the angle. Find the other side of the angle and see which scale it falls on. What is the number of horns at this time?
6. It should be noted that the protractor is divided into an outer ring and an inner ring. When the zero scale line is in the inner ring, the degree of the inner ring should be read, and when it is in the outer ring, the degree of the outer ring should be read.
(2) Draw any angle
1, the protractor can not only measure angles, but also draw any angles, not to mention straight lines, parallel lines, straight parallel lines and rulers. Let's talk about how to draw an angle with a protractor, which is a function that a ruler does not have (except for special angles).
2. First of all, we need to draw the vertex and one side of the angle, which coincides with the measurement of the angle. Vertex and one side can be drawn at will, and their positions do not affect the degree of the final angle. When finished, we need to overlap the vertex of the angle with the center of the protractor and the zero scale line.
3. How many degrees do you want to draw? Just click a little on the scale of how many degrees on the protractor, and then draw another ray with the endpoint of the drawn ray as the endpoint, passing through the point you just drew. Also, when you click a point, you should pay attention to whether your zero scale line is in the outer circle or the inner circle.