Appearance of protractor

The protractor is as shown in the figure:

1, the function of protractor

You can draw angles, measure angles, draw vertical lines and parallel lines, and measure inclination, verticality and levelness. It can be used as an internal and external right-angle crutch and can be opened and closed. Can also be used as a long and short ruler, intuitive and accurate reading, draw the specified size of the circle inch.

2. Invention of protractor

The Arabs divided the Boxer into 180 blocks, and the horn system was born. Then Arabs make protractors according to the angle system, and theory guides practice. With the development of commerce and architecture in BC, protractors also developed in various forms. Now, as a drawing tool, protractor is usually made of plastic or iron, and can draw the required angle as needed.

Often used in conjunction with compasses, it can draw angles, measure angles, draw vertical lines and parallel lines, and measure inclination, verticality and levelness. It can be used as an internal and external right-angle crutch to open and close, and can also be used as a long and short ruler to intuitively and accurately read out and draw a circle with a specified size.

The application of protractor is as follows:

1.？ Angle measurement: use a protractor to measure the angle. The center point of the protractor coincides with the vertex of the angle, and the zero scale line coincides with one side of the angle. Observing the scale on the protractor is the degree of the measured angle.

2.？ Drawing: You can draw an angle of a specified degree with a protractor. The center point of the protractor coincides with the vertex of the angle, and the zero scale line coincides with one side of the angle. Find the required degree on the protractor and mark it, then overlap the mark with the other side of the angle and draw the outline of the angle along the zero scale line.

3.？ Determine the center point: use a protractor to determine whether the point on the plane is on a straight line. Place the center of the protractor on a straight line and observe the scale on the protractor. If the included angle of two angles is equal, then the two points are on the same straight line.

4.？ Measuring Angle Deviation: A protractor can be used to measure the deviation between two angles. If the deviation between two angles is greater than 90 degrees, the two angles are complementary.