What is a protractor?

is a device for measuring angle between two intersection lines. The angle is measured in stages and the circle is defined as 360 degrees of the same size. First known protractors were designed in the 17th century sailors who need to portray courses on naval graphs.

The basic diagonal consists of a half piece of material with a degree of marking to the outer edge of the arch or curved part. The direct edge is located along one of the rows to be measured, and the number of degrees is determined according to where the other line passes through the arch.

Because it is half a circle, the basic protractor measures only angles up to 180 degrees. This is adequate in normal use, because the relationship between two lines can always be expressed as an angle of 180 degrees or less. If the original location location creates an angle greater than 180 degrees, it simply flips less than 180 degrees.

This is due to the symmetrical nature of the circle; Starting with a single line, the angle to the second intersection line can be measured by moving either in the laiftRU clockwise or counterclockwise. One direction will measure an angle of greater than 180 degrees and the other will measure the angle of less than 180 degrees. Both cannot measure more than 180 because they have to add up to 360, the number of degrees in a full circle.

6 The arch is attached to one arm and the other arm slips freely over it. A shoulder is placed on one line and the other arm turns out until it is parallel to the other line. The degree is then read from the arch. Astronomers often use the third type of protractor, which has made a fully circular piece of material. This allows them directly to measure angles between 0 and 360.

angel is generally used to measure existing lines, but can also be designed to help them draw. By attaching the rotary arm to the straight edge of the semicircular disk described above, you can draw lines with any angles. Such devices are most commonly used in the design of technicDrawings such as architectural plans.