# Types of angles ## Contents

• 1 Definition of the angle
• 2 types of angles
• 3 examples of types of angles
• 4 steps to draw an angle
• 5 Measuring angles
• 6 other section labels
• 7 Ref

## Definition of the angle

Angle (Angles) is the amount of distance or divergence confined between two straight lines converging with each other, where the point of convergence and intersection of the two lines is called the vertex of the angle (English: Vertex), while the two lines forming the angle are called the two sides of the angle , in other words, the angle Two beams start from the same starting point,  As for how to express the angle, it is done by naming it with three letters so that the angle of the angle is in the middle, or by naming its head only, unless it is a common angle with others. 

## Types of angles

The angles are classified according to their degree measurement into several types, including the following:  
• Right angles: are angles whose measurement is equal to 90 °. In other words, if the geometry of the geometry is brought up so that its right angles are placed on the existing angle, the result will be exactly the same because the two angles represent two angles that are 90 °.
• Sharp angles: are angles that measure greater than 0 ° and less than 90 °, in other words, are the angles whose measurements are smaller than the angles measured in the right triangle.
• Diffuse angles: are angles that measure more than 90 ° and smaller than 180 °, in other words, they are angles that measure more than the angle in the triangle of the existing drawing .
• Straight angles: are angles whose size is equal to 180 °.
• Reflected angles: are angles that measure greater than 180 ° and less than 360 °, in other words, are angles that measure more than the angles of straight, smaller than the full angles.
• Full angles: are angles that measure 360 ​​°, in other words, are angles that revolve a complete cycle; they start from a certain point and end up at the point from which they started.

## Examples of types of angles

• Example: classify the following angles (21 °, 360 °, 98 °, 102 °, 181 °, 5 ° , 100 °, 191 °, 90.5 °, 55 °, 232 °, 369 °, 270 °) into right angles, or Acute, obtuse, straight, complete, reflexive, or other, depending on the number of degrees, with the reason:
The solution: the angles are classified in the following table according to their measurements:
Angle measurement Angle type Reason
21 ° Acute angle Angle 21 ° is greater than 0 ° and less than 90 ° (0 ° <21 ° <90 °), thus it is considered an acute angle.
360 ° Full angle Angle 360 ​​° is the angle at which a full rotation occurs, thus it is considered a complete angle.
98 ° obtuse angle Angle 98 ° is greater than 90 ° and less than 180 ° (90 ° <98 ° <180), thus it is considered an obtuse angle.
102 ° obtuse angle Angle 102 ° is greater than 90 ° and less than 180 ° (90 ° <102 ° <180 °), thus it is considered an obtuse angle.
181 ° Reflected angle Angle 181 ° is greater than 180 ° and smaller than 360 ° (180 ° <181 ° <360 °), thus considered a reflection angle.
5 ° Acute angle Angle 5 ° is greater than 0 ° and less than 90 ° (0 ° <5 ° <90 °), thus it is considered an acute angle.
100 ° obtuse angle Angle 100 ° is greater than 90 ° and less than 180 ° (90 ° <100 ° <180 °), thus it is considered an obtuse angle.
191 ° Reflected angle Angle 191 ° is greater than 180 ° and smaller than 360 ° (180 ° <191 ° <360 °), thus it is considered a reflected angle.
90.5 ° obtuse angle Angle 90.5 ° is greater than 90 ° and smaller than 180 ° (90 ° <90.5 ° <180 °), thus it is considered an obtuse angle.
55 ° Acute angle Angle 55 ° is greater than 0 ° and less than 90 ° (0 ° <55 ° <90 °), thus it is considered an acute angle.
232 ° Reflected angle Angle 232 ° is greater than 180 ° and smaller than 360 ° (180 ° <232 ° <360 °), thus it is considered a reflected angle.
369 ° --- The angle 369 ° does not fall within the measurement of 0 ° -360 °.
270 ° Reflected angle Angle 270 ° is greater than 180 ° and smaller than 360 ° (180 ° <270 ° <360 °), thus it is considered a reflected angle.

## Steps to draw an angle

To draw an angle with a known size using a protractor and a ruler, there are a set of steps that must be followed to draw an angle with a specific measurement. For example, if a 50 ° angle drawing is required, the following steps are followed: 
• The ruler and protractor are provided for drawing the angle with them.
• A straight segment is drawn with a ruler, and the piece is called (Ab).
• The protractor is placed on the straight segment (AB), so that its center applies to point B.
• The protractor gradient, which starts from 0 ° at the rib (ab), is determined, then the 50 ° is located on the protractor with absolute precision.
• The 50 ° is indicated by a point or marker in the pen, and it is called point C.
• A straight line is drawn between points c and b.
After these steps, the acute angle ABC, whose measurement equals 50 °, is obtained.

## Measuring angles

The use of a protractor depends not only on drawing the angles , but is also used to find the measurement of angles in an easy and simple way. For example, if a measure of the angle ABC was requested using the protractor, the protractor is simply placed on the top of the angle B (the letter that is in the middle), so that it applies The starting line of the gradient with side a, b, and then the number exactly corresponding to side aj is read, while this number represents the measurement of the angle b in degrees, which is required. 

## Other angles labels

There are labels given on the corners, as follows: 
• The two adjacent angles: the two angles that share the same head of the angle and one of its sides; the other two sides of each of the angles are located on two different sides of the side of the joint side.
• The two complementary angles are the two angles whose sum is equal to 180 °; that is, the sum of their measures is equal to a straight angle.
• Two complementary angles: the angles whose sum is equal to 90 °; that is, the sum of their measurements equals a right angle.