When it comes to geometric shapes, polygons are an essential part of the equation.
These closed figures, with a minimum of three sides and three vertices, come in various types and have unique properties that make them intriguing subjects of study.
In this article, we will delve into the different types of polygons, including regular polygons, irregular polygons, convex polygons, and concave polygons, among others.
Key Takeaways:
 Types of polygons encompass a wide range of shapes and structures.
 Regular polygons have equal side lengths and angles.
 Irregular polygons have varying side lengths and angles.
 Convex polygons have all interior angles less than 180 degrees.
 Concave polygons have at least one interior angle greater than 180 degrees.
Definition of a Polygon
A polygon is a closed geometric shape made up of a finite number of straight line segments joined end to end.
It is formed by connecting several line segments, known as edges, and the endpoints of those edges are called vertices.
The term “polygon” is derived from the Greek words “poly” meaning “many” and “gon” meaning “angle,” indicating that polygons have many angles.
For a shape to be classified as a polygon, it must satisfy two conditions:
 It must be a closed figure, meaning that all the line segments connect to form a closed loop.
 It must have a minimum of three sides and three vertices.
Each side of a polygon intersects exactly two other sides at their endpoints, and no two sides cross each other inside the shape. Additionally, the sides cannot be curved; they must be straight lines.
Definition: A polygon is a closed geometric shape made up of a finite number of straight line segments joined end to end.
Properties of Polygons
Polygons have several properties that define their characteristics:
 Sides: The number of sides in a polygon determines its classification (e.g., triangle, quadrilateral, pentagon, etc.).
 Vertices: The points where the sides of a polygon meet are called vertices. The number of vertices also corresponds to the number of sides.
 Angles: Polygons have interior angles formed by the intersection of their sides. The sum of the interior angles in a polygon can be calculated using the formula (n – 2) × 180 degrees, where n is the number of sides.
 Diagonals: Diagonals are line segments connecting nonadjacent vertices in a polygon. The number of diagonals in a polygon can be determined using the formula n × (n – 3) ÷ 2, where n is the number of sides.
Understanding the definition and properties of polygons is essential when studying geometry and other related fields.
By exploring the different types of polygons and their characteristics, we can gain a deeper understanding of the fascinating world of geometric shapes.
Type of Polygon  Number of Sides  Number of Vertices  Interior Angle Sum  Number of Diagonals 

Triangle  3  3  180 degrees  0 
Quadrilateral  4  4  360 degrees  2 
Pentagon  5  5  540 degrees  5 
Hexagon  6  6  720 degrees  9 
Classification of Polygons
Polygons are geometric shapes that can be classified into different types based on various parameters such as the number of sides, side lengths, and interior angles.
Understanding the classification of polygons is essential to study their properties and applications.
Regular Polygons
A regular polygon is a polygon where all the sides are equal in length and all the interior angles are the same.
Some examples of regular polygons include squares, equilateral triangles, and regular pentagons.
Regular polygons have specific properties and formulas that can be used to calculate their area, perimeter, and other characteristics.
Irregular Polygons
On the other hand, irregular polygons have sides of unequal length and angles of unequal measure.
Unlike regular polygons, the sides and angles of irregular polygons vary. Examples of irregular polygons include scalene triangles, rectangles, and kites.
Irregular polygons have unique properties that can be explored and studied in detail.
Convex and Concave Polygons
Polygons can also be classified as convex or concave based on the measure of their interior angles. Convex polygons have all interior angles less than 180 degrees, and their vertices always point outwards.
Examples of convex polygons include regular triangles, quadrilaterals, and pentagons.
In contrast, concave polygons have at least one interior angle greater than 180 degrees, and their vertices can point both inwards and outwards.
Understanding the difference between convex and concave polygons is crucial when analyzing their properties and applications.
Overall, the classification of polygons provides a framework for organizing and studying these geometric shapes.
Whether regular or irregular, convex or concave, each type of polygon has its own properties, formulas, and characteristics that make them fascinating subjects of investigation in various fields.
Type of Polygon  Description 

Regular Polygon  All sides are equal in length, and all interior angles are the same. 
Irregular Polygon  Sides have unequal lengths and angles have unequal measures. 
Convex Polygon  All interior angles are less than 180 degrees, and vertices point outwards. 
Concave Polygon  At least one interior angle is greater than 180 degrees, and vertices can point both inwards and outwards. 
Regular Polygons
In geometry, regular polygons are a special type of polygon where all sides are equal in length and all angles are the same.
These polygons have a symmetrical and uniform appearance, making them aesthetically pleasing and mathematically intriguing.
One example of a regular polygon is a square. With four equal sides and four equal angles of 90 degrees, a square exhibits perfect symmetry and balance.
Other examples of regular polygons include equilateral triangles, where all three sides and angles are equal, and regular pentagons, which have five equal sides and angles.
Regular polygons possess unique properties that set them apart from their irregular counterparts.
For instance, regular polygons can be inscribed within a circle, with each vertex touching the circumference.
This property allows for easy calculation of the polygon’s area and perimeter using specific formulas.
Properties of Regular Polygons
Regular polygons have several distinct properties that can be analyzed and categorized. Some noteworthy properties include:
 Equal Side Lengths: All sides of a regular polygon are of equal length, which contributes to its symmetrical appearance.
 Equal Interior Angles: Regular polygons have congruent interior angles, meaning all angles within the polygon are the same.
 Diagonal Relationships: The diagonals of regular polygons exhibit specific relationships. For example, a regular hexagon has nine diagonals, while a regular octagon has twenty diagonals.
Regular polygons are not only mathematically fascinating, but they also appear frequently in nature and manmade structures. From the honeycomb cells of a beehive to the spokes of a bicycle wheel, regular polygons can be found all around us, showcasing their remarkable symmetry and inherent beauty.
Polygon  Number of Sides  Sum of Interior Angles (in degrees) 

Triangle  3  180 
Square  4  360 
Pentagon  5  540 
Hexagon  6  720 
Regular polygons offer a fascinating glimpse into the world of geometry, showcasing the harmony and patterns that exist within shapes.
From their precise angles to their symmetrically balanced sides, regular polygons continue to capture the curiosity and imagination of mathematicians, artists, and enthusiasts alike.
Irregular Polygons
Irregular polygons are a diverse group of geometric shapes that are characterized by having sides of unequal length and angles of unequal measure.
Unlike regular polygons, which have symmetrical sides and angles, irregular polygons have varying side lengths and angles.
Some examples of irregular polygons include scalene triangles, rectangles, kites, and more.
These polygons can be visually captivating due to their unique shapes and configurations.
Irregular polygons can pose interesting challenges in geometry, as their asymmetrical nature requires a different approach when analyzing their properties.
For example, determining the area of an irregular polygon may involve breaking it down into smaller, more manageable shapes, such as triangles or trapezoids, and calculating their individual areas before summing them up.
Likewise, measuring the perimeter of an irregular polygon may require carefully adding up the lengths of each side.
Irregular polygons offer endless possibilities for creative design and artistic expression. Their unique shapes can be found in nature, architecture, and various art forms, making them a fascinating subject of study for both mathematicians and enthusiasts alike. As we explore the world of irregular polygons, we unlock a world of infinite possibilities and limitless beauty.
Convex and Concave Polygons
When studying polygons, it is important to understand the distinction between convex and concave polygons.
Convex polygons have all interior angles measuring less than 180 degrees, and their vertices always point outwards.
On the other hand, concave polygons have at least one interior angle measuring greater than 180 degrees, and their vertices can point both inwards and outwards.
The difference between convex and concave polygons becomes apparent when examining their shapes.
Convex polygons have a simple and outwardly curved appearance, similar to a regular hexagon or a square.
Their interior angles add up to 360 degrees, and all the diagonals lie within the shape.
In contrast, concave polygons have more complex shapes with one or more indentations.
Their interior angles do not add up to 360 degrees, and some of their diagonals extend outside the shape.
To further illustrate the distinction, consider the following examples. A regular pentagon is a convex polygon because all of its interior angles are less than 180 degrees, and its vertices point outwards.
Conversely, a starshaped polygon with multiple points sticking inward is a concave polygon since it has at least one interior angle greater than 180 degrees.
Visualizing convex and concave polygons can help understand their properties and applications in geometry.
Convex Polygons  Concave Polygons 



Different Types of Polygons Based on Sides
Polygons are geometric shapes that can be classified based on the number of sides they have.
Different types of polygons with varying numbers of sides exhibit unique properties and characteristics.
The most common types of polygons based on sides include triangles, quadrilaterals, pentagons, hexagons, and more.
Types of Polygons Based on Sides:
1. Triangles: Triangles are polygons with three sides and three angles. They can be further classified into equilateral triangles (all sides and angles are equal), isosceles triangles (two sides and two angles are equal), and scalene triangles (all sides and angles are different).
2. Quadrilaterals: Quadrilaterals are polygons with four sides and four angles. Some common examples of quadrilaterals include rectangles, squares, rhombuses, and parallelograms. Each type of quadrilateral has its own distinct properties, such as equal side lengths or right angles.
3. Pentagons: Pentagons are polygons with five sides and five angles. There are different types of pentagons, such as regular pentagons (all sides and angles are equal) and irregular pentagons (sides and angles are different). Regular pentagons have unique properties, such as the sum of interior angles equaling 540 degrees.
4. Hexagons: Hexagons are polygons with six sides and six angles. They can be categorized as regular hexagons (all sides and angles are equal) or irregular hexagons (sides and angles are different). Regular hexagons have symmetrical properties, making them useful in various applications.
By understanding the different types of polygons based on sides, we can explore their specific properties and use them in various mathematical and realworld applications. Whether it be the angles of a triangle or the symmetry of a regular hexagon, each type of polygon offers its own set of fascinating characteristics.
Type of Polygon  Number of Sides  Example 

Triangle  3  Equilateral Triangle 
Quadrilateral  4  Rectangle 
Pentagon  5  Regular Pentagon 
Hexagon  6  Regular Hexagon 
Properties and Formulas of Polygons
Understanding the properties and formulas of polygons is essential in geometry and other related fields.
These mathematical tools allow us to calculate important aspects such as the area, perimeter, and interior angles of polygons.
Let’s explore some of the key properties and formulas that can help us analyze and solve problems involving polygons.
Area and Perimeter:
The area of a polygon is the measure of the space it occupies within its boundaries. The formula for calculating the area of a polygon varies depending on its type.
For example, the area of a triangle can be calculated using the formula A = (base x height) / 2, while the area of a regular polygon can be determined by multiplying the apothem (the distance from the center to any side) by the perimeter and dividing the result by 2.
The perimeter of a polygon is the total length of its boundary. To calculate the perimeter, we simply add up the lengths of all the sides.
For regular polygons, where all sides are equal in length, the perimeter can be determined by multiplying the number of sides (n) by the length of each side.
Interior Angles:
The interior angles of a polygon are the angles formed inside the shape. The sum of the interior angles in any polygon can be calculated using the formula (n2) x 180 degrees, where n represents the number of sides.
For example, a quadrilateral (a polygon with four sides) has a sum of interior angles equal to (42) x 180 = 360 degrees.
In addition to the sum of interior angles, we can also determine the measure of each individual interior angle in a regular polygon.
For regular polygons, the measure of each interior angle can be found using the formula 180 x (n2) / n, where n represents the number of sides.
This formula allows us to calculate the measure of each interior angle in polygons such as triangles, quadrilaterals, pentagons, and more.
Polygon Type  Area Formula  Perimeter Formula 

Triangle  A = (base x height) / 2  P = side1 + side2 + side3 
Rectangle  A = length x width  P = 2 x (length + width) 
Regular Polygon  A = (apothem x perimeter) / 2  P = n x side 
By understanding and utilizing these properties and formulas, we can solve a wide range of problems related to polygons.
Whether it’s calculating the area of an irregular polygon or finding the measure of an interior angle in a regular polygon, these mathematical tools provide a solid foundation for geometry and beyond.
FAQ
What is a polygon?
A polygon is a closed shape figure that has a minimum of three sides and three vertices.
How are polygons classified?
Polygons are classified based on the numbers of sides and vertices. There are various types of polygons, including regular polygons, irregular polygons, convex polygons, concave polygons, and more.
What is the definition of a polygon?
A polygon is a closed geometric shape made up of a finite number of straight line segments joined end to end.
It is formed by connecting several line segments, known as edges, and the endpoints of those edges are called vertices.
What are regular polygons?
Regular polygons have all sides equal in length and all interior angles the same. Examples of regular polygons include squares, equilateral triangles, and regular pentagons.
What are irregular polygons?
Irregular polygons have sides of unequal length and angles of unequal measure. The sides and angles of irregular polygons vary.
What are convex and concave polygons?
Convex polygons have all interior angles less than 180 degrees, and their vertices always point outwards.
Concave polygons have at least one interior angle greater than 180 degrees, and their vertices can point both inwards and outwards.
What are the different types of polygons based on sides?
Examples of different types of polygons based on sides include triangles, quadrilaterals, pentagons, hexagons, and more.
What are the properties and formulas of polygons?
Polygons have various properties and formulas that can be used to calculate their area, perimeter, interior angles, and more.
Conclusion
In conclusion, polygons are fascinating geometric shapes that come in different types and have unique properties.
They are classified based on the number of sides, side lengths, interior angles, and more. Understanding these classifications is fundamental in geometry and various other fields of study.
Regular polygons have sides of equal length and all interior angles are the same. Examples include squares, equilateral triangles, and regular pentagons.
Irregular polygons, on the other hand, have sides of unequal length and angles of unequal measure. Examples include scalene triangles, rectangles, and kites.
Another important distinction is between convex and concave polygons. Convex polygons have interior angles less than 180 degrees and their vertices always point outwards.
Concave polygons, on the other hand, have at least one interior angle greater than 180 degrees and their vertices can point both inwards and outwards.
Finally, polygons can also be classified based on the number of sides they have. Common types include triangles, quadrilaterals, pentagons, and hexagons.
Each type of polygon has its own unique properties and characteristics that can be explored further in geometry and related fields.