1, put the protractor on the corner so that the center of the protractor is aligned with the vertex of the corner.
2. Align and overlap the zero scale line of the protractor with the starting edge of one side.
3. The scale of the protractor scale line corresponding to the other side of the angle is the degree of this angle.
The protractor can draw angles, measure angles, draw vertical lines and parallel lines, and measure inclination, verticality and levelness. It can be opened and closed as an internal and external right-angle crutch, and can be used as a long and short ruler, which can be visually read out more accurately and draw a round inch with a specified size.
Angle is a mathematical concept. Used to describe the size of an angle, that is, the amount by which either of two intersecting lines must rotate when overlapping with another intersecting line. Degree is a unit to measure the size of an angle, and the symbol is 0. In practical application, the angle of an integer is accurate enough. When more accurate angle values are needed, such as measuring the latitude and longitude of a star or the earth in astronomy.
Besides being expressed in decimals, angles can be subdivided into angular minutes and angular seconds: 1 degree is 60 minutes (60'), and 1 is 60 seconds (60 "). For example, 40.1875 = 4011'15 ". In order to be more accurate, the angular seconds are expressed in decimals without adding units.
Type of horn:
1, acute angle: an angle greater than 0 and less than 90 is called an acute angle.
2. Right angle: An angle equal to 90 is called a right angle.
3. Oblique angle: An angle greater than 90 and less than180 is called obtuse angle.
4. Flat angle: The angle equal to 180 is called flat angle.
5. Optimal angle: an angle greater than180 and less than 360 is called optimal angle.
6. Bad angle: more than 0 and less than 180 is called bad angle, and acute angle, right angle and obtuse angle are all bad angles.
Fillet: An angle equal to 360 is called a fillet.
8. Negative angle: The angle formed by clockwise rotation is called negative angle.
9. Positive angle: the angle of counterclockwise rotation is positive angle.
10, zero degree angle: an angle equal to 0.