Nonagon is a two-dimensional geometric figure that consists of nine sides, nine vertices, and nine angles. It is also known as an enneagon. The word enneagon has Greek origins, where ‘ennea’ means nine and ‘gon’ means sides. It falls under the category of polygons.

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**Types of Nonagon**

### 1. Regular Nonagon

If all the sides of a nonagon are equal in length and all the angles are equal in magnitude, then such a nonagon is known as a regular nonagon. The magnitude of each interior angle of a regular nonagon is equal to 140°.

### 2. Irregular Nonagon

An irregular nonagon has different magnitude lengths and angles.

**Properties of Nonagon**

1. The sum of interior angles of a nonagon is equal to 1260°.

2. The sum of nine exterior angles of a nonagon is equal to 360°.

3. The sides of a nonagon are strictly straight lines and cannot be curved.

4. The interior of a nonagon can be divided into seven triangles.

5. A nonagon has 27 diagonals.

**Examples of Nonagon**

### 1. Coins

Some of the coins are shaped like a nonagon. Hence, one can easily observe the nonagon geometric shape in real life by looking at the outline of such coins.

### 2. Drinking Glass

Drinking glasses are generally shaped like a cylinder; however, some of the glasses are also manufactured in the shape of a nonagon.

### 3. Table

Study tables, coffee tables, etc. are manufactured in a variety of shapes and sizes out of which a nonagon is one of the most popular and preferred geometric shapes. The prime advantage of using a nonagon figure to construct tables is that it increases the capacity of the table to hold objects.

### 4. Dream Catchers

A dream catcher is a decorative item that consists of a netted handmade hoop. If you look closely at the boundary or the outline of a dream catcher, the netted pattern tends to form the shape of polygons such as a pentagon, hexagon, heptagon, or nonagon.

### 5. Architecture and Design

Nonagon geometric figure finds its prime application in the architecture and design domain. The patterns formed on the floors or on the rooftops of a building are usually shaped like a nonagon.

### 6. Star Pattern

If you connect all the diagonals of a nonagon, you can easily visualise the star pattern formed by it. Hence, star-shaped paper crafts are yet another example of nonagon geometric shapes in real life.

### 7. Ornaments

A number of ornaments such as pendants, earrings, etc. are shaped like a nonagon. Hence, such accessory items form a prominent example of the nonagon-shaped objects used in everyday life.

### 8. Dishes

Dishes are generally circular in shape; however, some of the plates and dishes are also shaped like a nonagon. The nonagon geometric shape adds a unique look to the utensils.

### 9. Mat

Kitchen and doormats are available in a variety of shapes and sizes out of which a nonagon is one of the most popular geometric shapes.

### 10. Fan

The outer rim of table fans is usually shaped like a nonagon.

### 11. Buildings

The US Steel Building situated in Pittsburgh is one of the best examples of buildings that are shaped like an irregular nonagon. One can easily locate the nine unequal sides forming the boundary of the building while looking at it from the top. Similarly, all houses of worship in the Bahá’í faith are a prominent example of a regular nonagon.