Why are all protractors made semi circular and not round n?

Because the degree of measuring a number angle is less than or equal to 180 degrees, as long as the inner angle of 180 degrees is used and measured, and the protractor is large, it is not convenient to measure the angle.

Design according to objective needs: can draw angles, measure angles, draw vertical lines, and parallel lines at will.

Measure inclination and verticality.

Horizontality, can be used as an inside and outside right-angle ruler, open, close, can be used as a length ruler can also be read more intuitively, and draw a circle of the specified size.

The product can be made of three types: a small stationery (mainly made of plastic) for primary and secondary school students; Type B teaching aids (mainly made of plastic) are used for school teachers; C-type tools (mainly made of stainless steel) are used in factories, workshops, carpentry, mechanics, repairmen, etc.

1. Measure the angle of an angle, and only need to measure the angle of no more than 180° to meet the requirements. For angles greater than 180°, we only need to measure its group angle (i.e. 360° minus this angle greater than 180°).

2. After being made into a circle, the area of the protractor becomes larger, which is inconvenient to use.

3. The semicircle has a straight edge, which can also be used as a ruler.

The above is what I have seen personally for reference.

To measure the angle of an angle, we only need to measure the angle of no more than 180 degrees to meet the requirements, and for the angle of more than 180 degrees, we only need to measure his group angle, that is, 360 degrees minus this angle of about 180 degrees.

Because the semicircle is 0 degrees, it is also an angle of 180 degrees, and if you change it to a circle, it is 360 degrees, and you will not be able to find the horizontal line.

Thank you for your interest.

Measure the degree of an angle, the degree of an angle is less than 180 degrees, so only 180 degrees is enough. And it's too big.

This is because if it is made round, it may be difficult to measure.

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Because the horn has edges, and the edges are rays. Semicircular, just one side is straight. Design according to objective needs:

Can draw angles at will, measure angles, draw vertical lines, parallel lines, measure inclination, verticality, horizontality, can be used as internal and external right-angle rulers, open, close, can be used as long and short rulers can also be read more intuitively, and draw a circle of the specified size.

The protractor has a wide range of materials, low cost, simple structure, easy to manufacture, strong practicability, large application market, and great investment benefits for the producer.

In order to make up for the singleness of the protractor in use and the inconvenience of carrying and storage, a multi-purpose method is generally adopted, so that the protractor has flexibility and comprehensive practical value, simple structure, novel and unique shape, reasonable design, so as to improve work efficiency and reflect social benefits.

Because if the protractor is fully circular, it cannot draw a straight line.

It is simple to make a semicircle, one side is a straight line to measure the angle, and it can also replace the ruler, which can be used to draw a straight line, and at the same time, it can also measure the angle greater than 180 degrees.

The protractor can draw angles, measure angles, draw vertical lines, parallel lines, measure inclination, verticality, and horizontality, and can be used as an internal and external right-angle ruler, open and close, and can be used as a long and short ruler to read out more intuitively, and draw a circle of the specified size.

It is easy to make a semicircle, with a straight line on one side to measure the angle, and it can also be used to draw a straight line instead of a ruler, and it can also measure an angle greater than 180 degrees. There are also some protractors that are fully circular, but cannot draw straight lines.

Because the semicircle is a 0 degree and an angle of 180 degrees, it is more convenient to use.

If you change it to a right angle of 90 degrees, you can't measure an angle greater than 90 degrees.

If you make him into a circle, that is, 360 degrees, you can't find a horizontal line.

You can draw angles, measure angles, draw vertical lines, parallel lines, measure inclination, verticality, and horizontality, and can be used as a right-angle ruler inside and outside, open and close, and can be read intuitively when the length and length of the ruler can be read more intuitively, and draw a circle of the specified size.

Extended Content:The protractor has a wide range of manufacturing materials, low cost, simple structure, easy to manufacture, strong practicability, large application market, and great investment benefits for the producer. You can draw angles, measure angles, draw vertical lines, parallel lines, measure inclination, verticality, horizontality, can be used as internal and external right-angle rulers, open, close, can be used as long and short rulers can also be read more intuitively, and draw the specified size of the inch.

In order to make up for the singleness of the protractor in use and the inconvenience of carrying and storage, a multi-purpose method is generally adopted, so that the protractor has flexibility and comprehensive practical value, simple structure, novel and unique shape, reasonable design, so as to improve work efficiency and reflect social benefits.

The protractor is semicircular rather than circular because it is easy to use, a circle with an angle of 360°, which is divided into two by a diameter and adopts a semicircle, whether the angle is greater than 180° or less than 180°, it can be accurately measured.

The protractor can draw angles, measure angles, draw vertical lines, parallel lines, measure inclination, verticality, and horizontality, and can be used as an internal and external right-angle ruler, open, close, and can be read more intuitively when the length of the ruler can be drawn to the specified size.

<> drawing tools, usually made of plastic or iron, can be used to draw the desired angle as needed. Often used with compasses.

The protractor has a wide range of manufacturing materials, low cost, simple structure, easy to manufacture, strong practicability, large application market, and great investment benefits for the producer.

In order to make up for the inconvenience of the use of the protractor in the use of single macro ribbon fiber and the inconvenience of carrying and storage, the multi-purpose method of one device is generally adopted, so that the protractor has flexibility and comprehensive practical value, the knot is simple and simple, the shape is novel and unique, and the design is reasonable, so as to improve the work efficiency and reflect the social benefits.

Make it into a semicircle and make it 360 degrees, and you can't find the horizontal line. If it is made at 90 degrees, angles greater than 90 degrees cannot be measured. So the protractor is semicircular.

If you make the protractor round, then you can't measure some obtuse angles. If the protractor is rounded, then it is impossible to set a 0 tick mark. Therefore, the protractor is made into a semicircle, which is easy to find 0, and the obtuse angle n can also be measured.

Because the garden is a 0 degree and a 180 degree angle, it will be more convenient to use. If you change it to a 90-degree right angle, you can't measure an angle greater than 90 degrees, and if you change it to a circle, that is, a 360-degree angle, you won't be able to find a horizontal line.

Because the semicircle is a zero degree, it is also a 360-degree angle and a center point, if there is no decoration TV cabinet circle, she will not be able to measure the angle, the angle has a vertex, and the attraction should be according to the medicine. You have to measure against the zero tick line of the center point to one of the sides of the horn, so that you can talk about the measurement, if it is a circle, there is no center point, and there is no place where there are no two corners, it is difficult to be easy, and sometimes it is easy to measure wrong.

If the protractor is 360 degrees, then it is not easy to find the level of the round one.

Because the garden is 0 degrees, it is also an angle of 180 degrees, if you change it to a circle of 360 degrees, you will not be able to find the horizontal line.

Because the semicircle is a connecting degree, it is also an angle of 180 degrees, so it is more convenient to use, if you change it to a 90-degree right angle. I can't measure a bigger number than him.

Because the semicircle is o degrees, it is also an angle of 18o degrees, so it is more convenient to use.

The semicircle is 0 degrees, and it is also an angle of 180 degrees, so it is more convenient to use.

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