Want to know proper Angle definition?

Before going deep into the topic, let us understand what is angle? According to the angles definition, the corner shape formed by intersection of two rays is called angle as shown below. Angle is derived from Latin word 'Angulus' which means corner. Angle is one of the important concept of geometry and can be applied to several geometric problems. So let us learn the way of measuring angles.
angle definition

Studying the way of Measuring angles:

The measure of angle totally depends on the opening between its two sides according to angle definition. Angles can be measured in degrees or radians. The conversion formula is π rad = 180 degrees. Protractor is a instrument used for measuring angles. The image below shows a protractor along with angle measuring technique.

measuring angles

Just keep the center point of the protractor to the vertex of angle with one side coinciding the protractor line as shown. Now check where the 2nd side cuts the protractor measure. That will be the angle in degrees. In our case it is 50 degrees as shown by dotted lines. Another way of measuring angles is by trigonometric formulas.

Generally angle definition classifies angles into 3 types as acute, right and obtuse. The angles whose measure is less than 90° is called acute angle, the one having 90° measure is called right angle and the one with measure greater than 90° is called obtuse angle. Hence the angle that we measured is acute in nature. Let us solve some angles examples to understand it better.

Solving angles examples:

The example of angles are given below to have a clear understanding of the subject.

(i) Convert 120 degrees angle in radians:

We know that 180 degrees = π rad. Hence 120 degrees = 120 x π / 180 = 2π/3. Hence 120 degrees equal 2π/3 rads.

(ii) Convert 30 degrees angle in radians:

30 degrees = 30 x π / 180 = π/6. Thus 30 degrees equals π/6 rads.

More topics in Angles
Adjacent Angles Vertical Angles
Corresponding Angles Alternate Interior Angles
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