Shapes have an innate appeal in the field of geometry. While squares and circles are ubiquitous in everyone’s day-to-day lives, there exists a lesser-known figure called the decagon, primarily known for its uniqueness and allure. The ‘deca’ in decagon signifies ten equal sides and ten equal angles. It depicts a beautiful amalgam of complexity and symmetry at the same time. Its elegant existence can be seen in the worldly creations.

So let us begin by understanding the geometric configurations of a decagon and then learn about its existence in the real world. This post will unfold how this versatile ten-sided figure has captured its essence in ancient civilizations, and also modern-day applications.

**How to identify a decagon when you see one**

The sides and angles of a decagon are governed by some properties, which are essential for identifying and classifying a figure as a decagon.

**Let us delve into the properties of a decagon:**

**1. The number of sides: **

A decagon has exactly ten sides, no more, no less. Count the sides and ensure that you are able to see each side distinctly.

**2. Check for the length of the sides:**

A decagon has ten equal sides. After you have counted sides and you are sure there are ten of them distinctively, check for the length of each side. If it is a decagon, each side will be of equal length.

**3. Take a close look at the angles:**

There are two types of decagon: a regular decagon and an irregular decagon. If all the interior angles of the polygon measure 144 degrees then it is classified as a regular decagon. If each of the angles measures different, then it is an irregular decagon.

**4. Is the figure symmetric?**

In the case of a regular decagon, you will find that it is symmetric. This means that if you were to divide the decagon into ten equal parts, you would find that each and every obtained part is a symmetry or a mirror image of the other 9 parts. Also, if you fold the decagon along the obtained lines of symmetry, you will observe that all the sides and interior angles align perfectly.

**5. How many diagonals do you find?**

If you try drawing diagonals from any single vertex or corner of a decagon to a non-adjacent vertex, you can draw five diagonals. This is true for each and every vertex.

**Real-life examples of decagons**

It may be a rare occurrence to spot decagons in real life but it is not uncommon. Take a look at some of the real-life examples of decagons.

**1. Decorative flooring tiles**

Interior and exterior designing of houses are all about making houses more aesthetic and appealing. Decorative flooring tiles are used to create decorative patterns that are either mosaic or simple patterns. Some of the shapes used for tiles are also decagonal.

**2. Clock faces**

Decorative wall clocks add to the aesthetic appeal of the interiors of homes. One such aesthetic wall clock is a clock that is shaped like a decagon. These clocks can be both decorative as well as functional timepieces, and enhance the appearance of the interiors of your home.

**3. Mirrors**

Apart from the need for dressing, mirrors are used in amusement parks for recreational purposes. Mirrors having a decagonal frame are used as decorative pieces and huge mirrors in amusement parks are decagonal and give you funny images when you see yourself in the mirror.

**4. Jewel **

Jewels are used by people for personal adornment. They are worn to enhance the appearance and are available in various forms such as bracelets, bangles, rings, earrings, nose rings, necklaces, and more. Occasionally, these jewels are designed in decagonal shapes that enhance their appeal.

**5. Canopies and Tents**

Canopies and tents are used for various outdoor events and trade shows. They are sometimes designed like decagons to enhance the aesthetic appeal and improve the functional design. A decagon-shaped canopy or tent is more sturdy due to more structural support.

**6. Algeria coins**

The study and practice of collecting ancient coins is called numismatics. In ancient Algerian numismatics, decagonal coins were very significant and have been preserved to this date for their aesthetic and ‘one-of-a-kind’ appeal. Thanks to their shape, these coins stand out from the crowd!

**7. Umbrella**

Umbrellas are a common sight during the rainy season as well as the hot summers. They are available in various color patterns some of them are multi-coloured, while the others are uni-coloured. Umbrellas also have various divisions. Some common divisions include 6, 8, 10, and 12. The ones with 10 divisions constitute a decagon.

**Wrapping it up!**

Although it may seem rare, decagons have a widely established presence in the real world. They have been significant since ancient times and today, the modern world uses products and gadgets that are shaped decagonally for their functionalities or simply to enhance the aesthetic appeal!

An engineer, Maths expert, Online Tutor and animal rights activist. In more than 5+ years of my online teaching experience, I closely worked with many students struggling with dyscalculia and dyslexia. With the years passing, I learned that not much effort being put into the awareness of this learning disorder. Students with dyscalculia often misunderstood for having just a simple math fear. This is still an underresearched and understudied subject. I am also the founder of Smartynote -‘The notepad app for dyslexia’,