#Protractor tool manual

It also includes the option of relative angle (relative zero). * Plumb line and digital inclinometer: used to measure the verticality of an object or the angle of inclination.

#Protractor tool manual

* Manual angle measurement: by moving each red line of the protractor you can choose the desired angle, in a range of 0 to 180 degrees. In case it is used as a plumb line or inclinometer it is a useful tool to perform some work in the area of construction, masonry, or carpentry, or simply if it is required to adjust the inclination of an object in the home. It is very useful in case you do not have a real protractor, and you need to perform some geometric task. The digitization of this group of artifacts was made possible through the generous support of Edward and Diane Straker.Protractor tool is an application that facilitates the task of measuring angles on an object or surface, and also works as a plumb instrument and digital inclinometer to determine if a plane or a surface are in perfectly vertical position (plumb).

Although there are not many academic books and articles specifically devoted to the protractor, the page of resources offers suggestions for further learning about the general history of drawing instruments. They were made in Italy, France, England, the United States, Switzerland, Germany, and Japan. These five-dozen examples also represent dates from about 1700 to 2000. Hart Combination Protractor, Rule, And Square, ca 1925Īs you will see by browsing through the images on the following pages, this diversity of shapes, sizes, and materials is reflected in the NMAH mathematics collections. They may be made of brass, steel, wood, ivory, or plastic. Protractors may have diameters as small as two inches or in excess of twelve inches. In part because of these different uses, protractors have been manufactured in many shapes: the familiar semicircle as well as circles, rectangles, squares, quarter-circles (or quadrants), and sixth-circles.

By the 18th century, the makers of mathematical instruments were explaining the manufacturing process for protractors, while the objects were beginning to appear in surveying textbooks and in introductions to geometry.īy the 19th century, machinists were devising a variety of specialized forms of protractors.ĭraftsman’s Protractor By Brown & Sharpe, 1887īy the 20th century, protractors had become commonplace in school mathematics. Regardless of who was first to describe the instrument, protractors entered the standard practices of navigators at sea and surveyors on land by the early 17th century. It is not clear that Blundeville invented the protractor, for other European mathematical practitioners wrote about similar objects around the same time period. As the title indicates, he used the protractor in the preparation of maps, particularly navigational charts for use at high latitudes. Although there were earlier instruments that were used for angle measurement in addition to other mathematical tasks, Thomas Blundeville described a tool specifically for drawing and measuring angles in his 1589 Briefe Description of Universal Mappes & Cardes. The protractors in the mathematics collections of the National Museum of American History (NMAH) illustrate stories of technical work and innovation in navigation, surveying, engineering, and war. However, protractors are not merely tools for enhancing learning but rather have a lengthy history of application in a variety of fields. Perhaps many people then never have reason to consider these objects again.

Americans typically encounter them in elementary or middle school, when they are learning to produce reasonably accurate geometrical figures in order to explore mathematical relationships between those figures.

Protractors are mathematical drawing instruments used to draw and to measure angles.