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# Why do you need a protractor

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A conveyor is a tool widely used inGeometry. At the same time, it is quite difficult to do without this tool as schoolchildren, who solve their first tasks, and engineers who perform complex geometric constructions.

The conveyor is a geometric tool used to measure angles.

## How protractor looks like

The main and mandatory parts of the protractor are twoKey element. The first of these is a ruler, divided into centimeter divisions. In this case, such a ruler is usually equipped with a reference point, which is used in the measurement process. The second element of the protractor is a goniometer scale, which is a semicircle, usually including divisions from 0 to 180 °. In this case, there are modified models of protractors, which have a full circular scale, that is, they allow measuring angles from 0 to 360 ° degrees.

Each angle scale contains a ruler for the values ​​of the angles in both the forward and reverse directions. This allows you to use a protractor to measure both sharp and obtuse angles.

Materials used for manufacturingProtractors, can be very different. The most common options for such materials are plastic and metal. The tree is currently used for these purposes somewhat less because such protractors typically are thicker and somewhat less convenient to use.

The accuracy of the measurements of each tool isIn direct proportion to its size. Thus, larger protractors allow measuring angles with greater accuracy, and small instruments give only an approximate idea of ​​the magnitude of the measured angle.

## How to use Protractor

With the help of a protractor, two basicTasks: measuring angles and building angles. So, to measure the angle, you need to place its vertex at the origin point, indicated on the protractor's ruler. Then you need to pay attention to the fact that the side of the corner, directed at the angle scale, crossed it. In case the length of this side is insufficient, it should be extended to the intersection of the angle scale.

After that, you need to look at which valueThe side of the corner intersects the specified scale. If the acute angle is measured, the desired value is less than 90 °, and when measuring the obtuse angle, one should use that part of the scale that contains fissions greater than 90 °.

The construction ofAngles with a protractor. First you should draw a line that will represent one of the sides, and its ending, which will become the vertex, will be placed in the reference point. Then, on the angular scale, the point should be the desired angle, which can be either sharp or blunt. After that, removing the protractor, connect the vertex of the future corner with the indicated point: as a result, you get the desired angle.

Why do you need a protractor Was last modified: July 5th, 2017 By
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