11 Facts About Angles That You Should Know Before Your Next Test

Abhijeet Modi
Oct 04, 2023 By Abhijeet Modi
Originally Published on Mar 14, 2022
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Age: 3-18
Read time: 3.0 Min

You must have heard your mathematics teacher mentioning a figure known as an 'angle.'

But what are angles and how much do you know about them? Let's find out!

Types Of Angles

So, imagine we draw a straight line from a point, called a vertex, and then draw another one from the same vertex, but in a different direction. Now, what we have between these two lines (referred to as rays) is called an angle. Here are a few different types of angles and their characteristics.

Two parallel lines inclined parallelly and forming zero degrees are called zero degree angles. When two equal straight lines intersect at a vertex that forms an angle of 90°, it's known as an acute angle. When two rays stand perpendicular to each other and form an angle of 90°, it is a right angle.

An angle between 90° and 180° formed by an intersection between two lines is an obtuse angle. Two equal rays joined end to end at a point form an angle of 180°, or a straight angle.

An angle between 180° and 360°, which also looks like a half-circle, is a reflex angle. An angle of 360° which looks like a complete circle is a complete angle. If two lines intersect, we get opposite angles, which are always equal. Angles sprouting from the same vertex are adjacent angles.

If the sum of two angles is 90°, we get complementary angles. If the sum of two angles is 180°, we get supplementary angles.

When a line crosses two parallel lines, it's known as a transversal. When an angle is formed outside a diagram or a shape, we get an exterior angle.

Angles that form within a diagram or shape are called interior angles. All interior angles of a triangle add up to 180°.

A triangle can be classified as an equilateral, scalene, or right-angle triangle based on its angles.

Importance Of Angles In Geometry

Angles come into play in various instances in your life.

Angles play an important role in the study of geometry by helping us define and study polygons like triangles and quadrilaterals.

Angles are also important when it comes to the study of trigonometry, which is again important for determining directions and then using a compass to find the correct route.

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Application In The Real World

But there's more to angles than what's on the page in your geometry book. Wait until you read about their usage in real life.

Angles play a vital role in architecture.

Angles are also important in building furniture, which, like architecture, demands precise definitions and measurements.


What are the seven types of angles?

There is the acute angle, obtuse angle, right angle, straight angle, reflex angle, full angle, and zero angle.

What are two basic facts about angles?

If the sum of all angles on a line is 180°, it is a complementary angle, and if the sum of the angles is equal to 90°, it is a supplementary angle.

What are the operating principles when it comes to angles?

Angles in a triangle, straight line, and co-interior angles add up to 180°. Angles in a quadrilateral, and around a point, add up to 360°. Vertically opposite and alternate angles are always equal.

Why do we need angles?

Angles are vital to the study of polygons, including triangles and quadrilaterals.

When was the angle created?

Angles were first discovered by Greek mathematicians Euclid and Carpus of Antioch, and the philosopher Eudemus.

What is the smallest angle?

The zero angle.

What is a full angle?

A 360° angle.

Can an angle be negative?

Yes, angles measured in clockwise directions are negative.

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Written by Abhijeet Modi

Master of Computer Science

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Abhijeet ModiMaster of Computer Science

An experienced and innovative entrepreneur and creative writer, Abhijeet holds a Bachelor's and Master's degree in Computer Application from Birla Institute of Technology, Jaipur. He co-founded an e-commerce website while developing his skills in content writing, making him an expert in creating blog posts, website content, product descriptions, landing pages, and editing articles. Passionate about pushing his limits, Abhijeet brings both technical expertise and creative flair to his work.

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