1. Know the protractor: A protractor is generally a round ruler with a scale of 0 to 180 degrees on it. The center point has a small hole for placing the vertex of the corner.
2. Choose the appropriate scale: there are scales of different sizes on the protractor, such as 1 degree, 5 degrees, 10 degrees, etc. Choosing the right ruler can help you measure the angle more accurately.
3. Place the protractor: place the protractor on the corner so that the center point of the protractor coincides with the vertex of the corner.
4. Reading: Start from the center of the protractor and find the scale on the other side of the angle along the selected scale line. This reading is the degree of the angle.
5. Pay attention to the direction: when measuring the angle less than 180 degrees, you need to pay attention to the direction and start reading from 0 degrees; When measuring an angle greater than 180 degrees, the protractor must be rotated along the scale until the 0 degree of the outer ring coincides with the 0 degree of the scale, and then the reading should be taken from the outer ring.
6. Record the result: Record the measured angle for future use.
Use of protractor:
1. Measuring Angle: The protractor can be used to measure any angle, whether it is acute, right or obtuse. Select the corresponding scale on the protractor, and then overlap the center point of the protractor with the vertex of the angle, and you can read the size of the angle.
2. Draw angles: In addition to measuring angles, protractors can also be used to draw angles of a specific size. Just fix the center point of the protractor at a certain position, and then select the required scale, you can draw the angle of the corresponding size.
3. Calculate the sum or difference of angles: It is convenient to calculate the sum or difference of two angles with a protractor. You only need to add or subtract the tick marks corresponding to two angles to get the result.
4. Solving geometric problems: When solving some geometric problems, a protractor is often used to measure angles or verify the relationship between angles. For example, when it is proved that triangles are congruent or similar, the conclusion can be verified by measuring the corresponding angles.
5. Auxiliary learning: In the process of learning mathematics, protractor is also a very useful auxiliary tool. By using protractor, we can better understand the concept and properties of angle and improve our geometric knowledge.