Top 3 Amazing Facts about Types of Triangles

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Updated on: Educator Review By: Michelle Connolly

Triangles, just what are they?

Triangles are some of the most fundamental and versatile geometric shapes in the world of mathematics and beyond. They serve as the building blocks for more complex shapes and have a wide range of applications in various fields and many different types of triangles.

What makes triangles unique is their simplicity and their essential role in geometry.

A triangle is a polygon with precisely three sides and three angles. These three sides are made up of straight lines, and the angles between them create the triangle’s distinctive shape.

Triangles come in different varieties, each with its unique characteristics. Equilateral triangles have all three sides and angles equal, making them exceptionally balanced and symmetrical.


Types of Triangles

A triangle is a two-dimensional shape with three straight sides and three angles.

A triangle has three sides, three vertices, and three angles. The sum of the three interior angles of a triangle is always 180°. The sum of the length of two sides of a triangle is always greater than the length of the third side.

2D shape properties – Different Types of Triangles. A fun math video to help teach your child the 2D shape properties of triangles. Explore the different types of triangles – isosceles, equilateral, right-angled, and scalene and their properties. Learn about the different angles and properties and help your child understand the properties of each different triangle type.

Today we are going to learn about the different types of triangles.
Hi, I am Mr. Triangle. I have 3 sides and 3 angles.
Did you know that there are 3 types of triangles according to their angles and another three types of triangles according to their side’s length?

What are the kinds of triangles according to sides?

According to the length of sides, triangles can be classified into 3 categories i.e., scalene, Isosceles, and Equilateral triangles.

First types of triangles according to their side’s length:
1- Isosceles: I have 2 sides of equal length and one side that is different. I have 2 equal angles. You can find me in objects like:
An ice cream cone, the Eiffel Tower in France, or a slice of Pizza!
2- Equilateral: I have 3 sides of equal length and my 3 angles are the same, 60 degrees!
I can be a road sign, a pool ball rack, or a Doritos!

3- A scale triangle is a triangle with no sides of equal length. An isosceles triangle is a triangle with two sides of equal length. An equilateral triangle is a triangle with three sides of equal length.

Second types of triangles according to their angles: 

1- Right-angled: One of my angles is always 90 degrees.
You can find me in sandwiches, a triangular ruler, or a ramp!

2- An acute angled triangle has three angles less than 90 degrees.

3- Obtuse angled triangle, has one angle greater than 90 degrees.
Look around you and try to find other examples!

  • Bermuda Triangle. …
  • Traffic Signs. …
  • Pyramids. …
  • Truss Bridges. …
  • Sailing Boat. …
  • Roof. …
  • Staircase and ladder. …
  • Buildings, Monuments, and Towers.

Triangles are everywhere, can you work out which type of triangle I am?

types of triangles,shapes LearningMole

Shapes and symmetry:

  • An equilateral triangle is a triangle with all three sides of equal length. …
  • An isosceles triangle is a triangle with two sides of equal length. …
  • A right-angled triangle is a triangle with one angle that is a right angle.
  • A scalene triangle is a triangle with all sides of different lengths.

Triangle is some of the simplest shapes there are. But this doesn’t mean that they are not important!

A triangle is a three-sided polygon and comes in a variety of flavors. Some have to do with the length of the triangle’s sides: equilateral — where all the sides (and all the angles) are the same size; isosceles — where two of the sides (and two of the angles) are the same size; and scalene — where none of the sides (or angles) are the same. The angles inside the triangle are also important. The sum of the angles is always 180°.

You can have acute triangles, where all the angles are less than 90°, and obtuse triangles, where one of the angles is greater than 90°. And of course, you can get right-angled triangles — one of the most influential mathematical shapes, inspiring Pythagoras’ Theorem and trigonometry.

But triangles aren’t just mathematically significant, they are also fundamental to the way we build our environments, both physical and virtual. Triangles are special because they are exceptionally strong. Out of all the two-dimensional shapes, we can make out of straight struts of metal, only a triangle is rigid.

All other shapes can be deformed with a simple push if the shape is hinged at the corners (for example, a rectangle can be pushed over into a parallelogram). But not the trusty triangle, which explains its ubiquitous use in construction, from pylons to bracing.

Triangles are also special because they are the simplest polygon — a common approach to a tricky geometrical problem, such as analyzing a complex surface, is to approximate it by a mesh of triangles. This approach is also used in the real world to achieve some exotic shapes we now see in modern architecture, such as the curved shape of 30 St Mary’s Axe, aka the Gherkin, or the canopy over the courtyard in the British Museum.

One shape is a favorite among architects, the triangle. The triangle is the strongest shape, capable of holding its shape, having a strong base, and providing immense support. 

Some of the world’s most famous architectural marvels like the Eiffel Tower, the Great Pyramids of Giza, and the Louvre Pyramid use the support of triangles to make beautiful, durable structures.

Two of the most used triangles in architecture are the 30⁰, 60⁰, and 90⁰ triangles and the 45, 45, and 90⁰ triangles.

Fun Triangle Facts: Unveiling the Secrets of the Strongest Shape!

Triangles are more than just three sides and a bunch of angles! They hold some fascinating facts that make them truly unique and remarkable in the world of shapes. Let’s dive into the exciting world of triangles and discover what makes them so special:

1. The Unbreakable Trio: Rigidity Rules!

Did you know that triangles are the champions of rigidity in the shape world? Unlike other shapes, they cannot be deformed without breaking! Imagine a square made of sticks connected at the corners. If you push on one side, the opposite side bulges outwards, changing the shape. But with a triangle, no matter how much you push or pull, its sides remain fixed, making it incredibly strong and stable. This property is why triangles are used in building bridges, roofs, and even airplanes, where strength and stability are crucial.

2. The 180-Degree Angle Adventure:

Ever wondered why triangles have only three sides? Well, it’s not just about the number of sides, it’s also about the angles they create! The sum of all the angles inside any triangle will always equal 180 degrees. This is a magical rule that applies to every single triangle, regardless of its size or shape. So, the next time you see a triangle, grab a protractor and measure its angles. You’ll be amazed at how they always add up to 180 degrees!

3. The Mighty Equilateral: A Champion Among Triangles!

Not all triangles are created equal (pun intended!). Among the different types of triangles, the equilateral triangle holds a special place. An equilateral triangle is one where all three sides are equal and all three angles are also equal (each measuring 60 degrees). But its claim to fame doesn’t stop there! Equilateral triangles are considered the strongest possible shape when it comes to resisting bending (per unit area). This makes them ideal for structures like bridges and trusses where strength and weight distribution are key factors.

So, the next time you encounter a triangle, remember these fun facts! They are not just ordinary shapes; they are champions of rigidity, masters of angles, and even the strongest shape in their own right. Keep exploring the world of shapes and discover the amazing properties and secrets they hold!

Unveiling the Mystery of Angles: Exploring the 3 Triangle Categories

Triangles are fascinating shapes, not just because of their sides, but also because of the angles they form! Depending on the measure of these angles, triangles can be categorized into three distinct groups:

1. The Acute All-Stars (All Angles Less Than 90 Degrees):

Imagine a triangle where all three angles are sharper than a right angle (less than 90 degrees). These triangles are called acute triangles. They are like enthusiastic athletes, always energetic and sharp, representing angles that haven’t yet reached the right angle “finish line.”

2. The Right Angle Champions (One Angle Exactly 90 Degrees):

Some triangles take a different approach. They have one angle that forms a perfect 90-degree corner, just like a square corner. These champions are called right triangles. They are the perfect balance between acute and obtuse triangles, holding their ground with a sturdy 90-degree angle.

3. The Obtuse Outliers (One Angle Greater Than 90 Degrees):

Not all triangles follow the “all angles under 90 degrees” rule. Some triangles have one angle that’s a bit of an outlier, exceeding the 90-degree mark. These triangles are called obtuse triangles. They are like individuals who march to the beat of their own drum, showcasing an angle that stands out from the rest.

But how do we actually measure these angles?

Enter the protractor, a handy tool shaped like a half-circle with markings from 0 to 180 degrees. Here’s how to use it:

  1. Place the flat edge of the protractor on one side of the angle you want to measure, aligning the center point of the protractor with the vertex (point) of the angle.
  2. Line up one of the protractor’s arms with the other side of the angle.
  3. Look at the scale marked on the curved edge of the protractor and read the number where the second arm of the angle intersects the scale. This number represents the measure of the angle in degrees.

Hands-On Triangle Adventures: Building, Exploring, and Creating with Triangles!

Triangles are more than just cool facts and figures; they’re also a gateway to fun and engaging activities! Get ready to unleash your creativity and explore the world of triangles with these hands-on adventures:

1. Straw/Toothpick Triangles:

  • Materials: Straws or toothpicks, pipe cleaners (optional), tape (optional)
  • Instructions:
    • Grab your straws or toothpicks and start building! Experiment with different lengths to create various triangle sizes.
    • For added stability, use tape to secure the ends of the straws or toothpicks at the connection points.
    • If you have pipe cleaners, bend them into different shapes and connect them to the straws/toothpicks to create unique and colorful triangles.
  • Challenge: Can you build different types of triangles (equilateral, isosceles, scalene)? See how many triangles you can construct with a limited number of straws/toothpicks.

2. Triangle Scavenger Hunt:

  • Materials: None required, just your surroundings!
  • Instructions:
    • Embark on a thrilling “triangle hunt” in your house, classroom, or even outside!
    • Keep your eyes peeled for objects that resemble triangles, from slices of pizza to rooflines of houses.
    • Once you find a triangle, describe its properties (size, type, location). You can even take pictures or draw them in a notebook to document your discoveries.
  • Challenge: Time yourself to see how many triangles you can find within a set time limit. Play with friends and see who can spot the most diverse or unique triangles!

3. Playdough/Paper Triangle Creations:

  • Materials: Playdough (different colors optional), construction paper, scissors, markers (optional)
  • Instructions:
    • Playdough Power: Get creative with playdough! Mold it into various shapes and sizes, focusing on creating triangles. Experiment with different techniques like rolling, flattening, and pinching to form diverse triangles.
    • Paper Precision: Grab some construction paper and unleash your inner artist! Cut out triangles of different sizes and colors. You can use rulers or stencils for guidance or freehand your shapes for a more creative touch. Decorate your triangles with markers, crayons, or stickers to personalize them.
  • Challenge: Combine both materials! Use playdough as a base to stick your paper triangles on, creating unique 3D shapes and structures. You can also use paper triangles to form larger shapes like squares, pentagons, or even a house!

Using Triangles in Design and Architecture: Building on Strength and Stability

Triangles are more than just fascinating shapes; they are the building blocks of strong and stable structures in the world of design and architecture! Let’s explore how triangles are used and even design our own creations:

1. The Power of Three: Why Triangles Rule the Stability Game!

Unlike squares or rectangles, which can easily deform under pressure, triangles possess a unique property called rigidity. This means that no matter how much force is applied, the sides of a triangle remain fixed, making it incredibly resistant to bending or collapsing. This remarkable characteristic makes triangles the go-to shape for building strong and stable structures.

Imagine a bridge: The triangular trusses used in its construction distribute the weight evenly, preventing the bridge from sagging or breaking under pressure. Similarly, the rooftops of many houses are built using triangular shapes to ensure they can withstand wind, rain, and snow.

2. From Pyramids to Skyscrapers: Real-World Examples of Triangle Power!

The use of triangles in design and architecture can be seen throughout history:

  • The Great Pyramids of Giza: These ancient wonders stand tall even after thousands of years, thanks in part to their pyramidical shape, which is essentially four triangles coming together at a point.
  • The Eiffel Tower: This iconic landmark utilizes a latticework of triangles in its design, providing immense stability to its towering structure.
  • Modern Skyscrapers: Many modern skyscrapers incorporate triangular elements in their facades or support structures, contributing to their impressive heights and resilience.

3. Design Your Own Triangle Masterpiece!

Now, it’s your turn to unleash your inner architect! Here’s a fun activity:

Materials: Cardboard, straws/toothpicks, tape, markers (optional)


  1. Plan your masterpiece: Sketch out a design for a structure using triangles as the main building blocks. Think about what you want to create: a bridge, a house, a tower, or something entirely new!
  2. Cut and connect: Cut out triangles from cardboard. Use straws or toothpicks as connectors and tape them securely to the cardboard triangles to form your structure.
  3. Get creative: Decorate your creation with markers, paint, or other materials to add personality.

FAQ (Frequently Asked Questions)

Q: Why are triangles not used in all buildings?

A: While triangles are fantastic for providing strength and stability, other factors like design aesthetics, functionality, and cost also play a role in architectural decisions. Additionally, different shapes can be combined to create strong structures, not just triangles.

Q: Are there other shapes used in design and architecture besides triangles?

A: Absolutely! Squares, rectangles, circles, and other shapes are also used in various ways, often in combination with triangles or other shapes to achieve specific design goals and functionalities.

Q: Where can I learn more about famous buildings that use triangles?

A: Many online resources and books explore famous buildings and architectural styles, often highlighting the use of specific shapes like triangles. Additionally, visiting museums or historical sites can offer opportunities to see these structures in person and learn more about their design and construction.


Triangles are more than just shapes on a page; they are powerful tools used in design and architecture to create strong, stable, and awe-inspiring structures. From ancient pyramids to modern skyscrapers, triangles have played a crucial role in shaping our world.

This article has explored the unique properties of triangles and their fascinating applications in design and architecture. We have also encouraged you to put your creativity to the test by designing your own triangle structure. Remember, the world of design and architecture is full of possibilities, and triangles are just waiting to be your next building block for imaginative creations!

Explore the previous examples and problems, and you will find yourself getting the necessary knowledge and information to fully grasp the concept of The triangle So, keep on visiting our LearningMole.

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