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How Many Sides Does a Polygon Have

Definition of a polygon

A polygon is a closed geometric figure with straight sides that encircle a flat surface. It consists of at least three line segments that meet only at their endpoints to form a shape. Polygons can have any number of sides, with the most basic being the triangle, which has three sides. Each side must be straight, and each angle must be less than 180 degrees. The sum of interior angles in a polygon is (n-2) × 180 degrees, where n is the number of sides.

Interestingly, regular polygons are polygons with congruent sides and angles, such as a square or hexagon. In contrast, irregular polygons are those with varying lengths of sides or non-uniform angles. Unique properties associated with polygons include symmetry across an axis, congruent opposites and consecutive sides and opposite angles equaling each other.

According to National Geographic, some natural formations such as basalt columns and honeycomb structures resemble regular polygons due to their uniform shapes and patterns. Why settle for irregular when you can have a regular polygon with a guaranteed number of sides?

Regular polygons

To understand regular polygons with their characteristics, ‘How Many Sides Does a Polygon Have’ with its section on regular polygons introduces you to their concepts. You’ll explore the explanation of regular polygons and an illustrative example of a regular polygon to get a deeper understanding of the sub-sections.

Explanation of regular polygons

Regular polygons are two-dimensional shapes that have sides of equal length and internal angles with equal measures. In simpler terms, these are closed figures consisting of straight lines that are uniform in size and shape. The most basic regular polygon is the equilateral triangle, which has three equal sides and three angles of 60 degrees each. Other examples include squares, pentagons, hexagons, octagons, and more.

Each regular polygon has its own set of unique properties, such as the number of sides and internal angles. These properties determine the exterior angle at each vertex and the symmetry of the shape as a whole. For instance, a square has four equal sides and four 90-degree internal angles that add up to 360 degrees. Its exterior angle at each vertex is thus 90 degrees as well.

Additionally, regular polygons can be inscribed within circles or circumscribed around them. The ratio between the perimeter (or circumference) of the polygon and the diameter of its corresponding circle remains constant for all regular polygons with n sides. This ratio is known as the pi approximation or Apollonius’ constant.

It’s interesting to note that ancient Greek mathematicians were fascinated by regular polygons and explored their properties extensively. A famous mathematical treatise called Elements by Euclid introduces many fundamental concepts related to these shapes even today.

Who needs irregular shapes when you can have the perfection of a regular polygon? It’s like having a symmetrical piece of art that’s also great at geometry.

Example of a regular polygon

A regular polygon is a two-dimensional figure with equal length sides and angles. An instance of such a polygon is showcased below.

Number of Sides Side Length (in units) Interior Angle (in degrees)
4 5 90

It is important to note that all regular polygons have symmetry around their center point and the sum of internal angles in these shapes is (n-2)180, where n represents the number of sides.

Pro Tip: The formula used to calculate the interior angle in a regular polygon is [(n-2)180]/n, where n represents the number of sides.

Irregular polygons are like rebellious teens, they refuse to follow any rules and end up causing chaos in geometry class.

Irregular polygons

To understand irregular polygons, with an emphasis on explanation and example, delve deeper into this area. Appreciate how intricate they can be and gain more knowledge about their shapes and sizes.

Explanation of irregular polygons

Irregular polygons are defined as those polygons which have sides and angles of different measures. These shapes do not possess the usual symmetry in their structure, making them unique from regular ones. They cannot be classified based on any set pattern, and each irregular polygon is distinct from the other.

A crucial aspect of these polygons is that they do not have to be convex; they can also be concave. The concave polygons have at least one interior angle measure greater than 180° and may contain “cut-off” corners similar to a piece of pie with one slice missing.

Interestingly, irregular polygons with equal side lengths exist known as equilateral irregular polygons or deltoids. Their sides are all equal but their interior angles differ in measure.

Studies by mathematicians found unexpected patterns arising for the perimeter to area ratio of an irregular polygon, in which it steadily increased up to a particular level before eventually decreasing again.

Sorry, did someone just steal a slice of pizza from this irregular polygon? Because it looks like it’s missing a piece.

Example of an irregular polygon

A prime instance of a non-uniform-shaped figure is the atypical polygon. The shape of an irregular polygon is often unpredictable, with unequal angles and sides that do not match.

Below is a visual representation of the unconventional polygon:

Sides Length (cm)
AB 5
BC 4
CD 6
DE 3
EA 7

To note, the sum of all interior angles in an irregular polygon can vary based on its geometric properties. The illustrated polygon mentioned above has an interior angle value exceeding much greater than ten degrees.

An interesting anecdote about irregular polygons includes their use in architectural design software that calculates the area for these unpredictable shapes. Before modern technology, architects and builders had to manually examine these shapes and estimate their dimensions, often resulting in mistakes and uneven building foundations.

Who needs symmetry when you can have a polygon with an odd number of sides? It’s like the rebellious teenager of geometric shapes.

Number of sides in a polygon

To understand the number of sides in a polygon, you need to know the formula and examples of polygons. The formula for calculating the sides is the key to discovering how many sides a polygon may have. Additionally, examples of different types of polygons can aid in your understanding of the concept.

Formula for calculating the number of sides in a polygon

A polygon is a two-dimensional shape with straight sides. The formula for determining the number of sides in a polygon brings great insight into geometry problems.

  • A polygon has at least three sides and angles.
  • If we know all the interior angles of the polygon, then we can calculate the number of sides using the formula n = 180 (x – 2) / x, where x is an interior angle.
  • If we know all the exterior angles of the polygon, then we can find n by dividing 360 by each exterior angle and summing up these quotients.
  • A regular polygon has equal side lengths and equal interior angles. Its number of sides can be found using the formula n = 360 / θ, where θ is an interior angle measurement in degrees.
  • The sum of all exterior angles of any convex polygon equals 360 degrees, which means its number of sides will always be smaller than vertices.

Remarkably, polygons have been studied for thousands of years across cultures like ancient Greece and Egypt. Mathematicians Euclid and Archimedes explored polygons extensively in their works.

By mastering this formula, you can determine various attributes about polygons with ease. Who needs to count sheep when you can count the sides of polygons? Trust me, it’s just as effective for falling asleep.

Examples of polygons and their number of sides

Polygons are shapes that have straight sides and angles. Some examples of polygons and the number of sides they have are:

Triangle 3
Square 4
Pentagon 5
Hexagon 6
Heptagon 7

Other polygons include octagons with eight sides, nonagons with nine sides, and decagons with ten sides.

It is important to note that the number of sides in a polygon can affect its properties, such as its angles and area. Mathematicians study these properties extensively to gain a deeper understanding of geometry.

Pro Tip: To find the sum of the interior angles of a polygon, use the formula (n-2) x 180, where n is the number of sides in the polygon.

Why settle for a boring square when you can have a hexagon? It’s like upgrading from a Honda to a Ferrari.

Common types of polygons

To identify various types of polygons with their unique properties, the article introduces the section on ‘Common types of polygons.’ Understanding these shapes is crucial for mathematicians and engineers in the real world. The section covers polygons ranging from the triangle, quadrilateral, pentagon, hexagon to the octagon.


For the first topic under discussion, we delve into a widely-known polygon commonly referred to as the three-sided figure. A triangle consists of three vertices, three edges and can be classified as either acute, obtuse or right-angled.

Now, moving to a more insightful aspect of this shape; let’s take a look at some details about triangles that you might not know yet. For instance, the sum of the interior angles in any triangle is equal to 180 degrees. Additionally, the longest side of every triangle is always opposite from the largest angle.

To showcase this information visually, we have constructed a table encompassing various types of triangles sorted by their unique features:

Triangle Type Description
Acute All angles are less than 90 degrees
Obtuse One angle is greater than 90 degrees
Right-Angled Contains a 90 degree angle between two sides
Equilateral All sides are equal in length
Isosceles Two sides are equal in length

In adherence to our formal tone, it’s helpful to remember that an angle must never exceed 180 degrees and therefore excludes the possibility of a four-sided polygon with only right angles. Interestingly enough, there is evidence to suggest ancient Egyptians used geometry principles from triangles for building pyramids.

Lastly, let me share an interesting story about how mathematicians examined complex geometric shapes during their quest for knowledge about polygons such as triangles. The ancient Greek philosopher Plato was particularly fascinated with geometry which he believed was necessary for us to observe and understand our world better. He was devoted to teaching others about geometric theories through his writings and conversations on Euclidean Geometry which proved invaluable in modern-day mathematical research and practices.

Who knew that a shape with three sides could be so interesting? Welcome to the world of quadrilaterals, where rectangles are just squares with commitment issues.


A four-sided polygon with straight sides and angles is known as a four-cornered figure. It is also referred to as a rectangular, parallelogram, or diamond-shaped figure.

Below is a table that showcases the different types of quadrilaterals and their unique features:

Quadrilateral Definition Properties
Rectangle A quadrilateral with four right angles. Opposite sides are parallel and equal in length; all internal angles are 90 degrees.
Parallelogram A quadrilateral with two pairs of parallel sides. Opposite sides are equal in length; opposite angles are equal in measure.
Trapezium (Trapezoid) A quadrilateral with one pair of parallel sides. The other two sides aren’t parallel, so the angles on each side are not equal.
Rhombus A quadrilateral with four equal-length sides and opposite angles. All internal angles have identical measures (opposite angles); diagonals bisect each other at their intersection point perpendicularly.

It is important to note that a square is also a type of rectangle, parallelogram, and rhombus.

When identifying quadrilaterals, it’s essential to understand their properties to avoid confusion between similar shapes.

When measuring diagonal lengths for rectangles and rhombuses, utilize the Pythagorean Theorem to calculate accurate measurements.

Additionally, when determining if a shape is either a trapezium or trapezoid (depending on region), verify which school system language they learned from since the two terms can have different meanings depending on where you’re from.

Why settle for a square when you can have the extra angle and drama of a pentagon?


This five-sided geometric figure is known for its popularity in many fields, including arts, mathematics and architecture. It has five angles and five sides, each of equal length. A pentagon can come in various forms like regular or irregular.

One fascinating property of a regular pentagon is its golden ratio. It is unique because when you draw a line between two opposite corners of a regular pentagon, it will divide into two parts which have the same proportion as the whole figure itself! This makes it visually appealing and popular in architectural designs.

Notably, scientists found evidence of a naturally occurring gigantic underground pentagon-shaped mountain range on Venus called The Beta Regio Mountain.

(Source: National Geographic)

Six sides may make for a hexcellent polygon, but don’t be hexited just yet – there are still five more shapes to go!


With six sides and six angles, a geometric shape with the name of this semantically analyzed variation is known as a figure with six edges. A hexagon has interior angles that add up to 720 degrees, and all sides are equal in length. It is classified as a convex polygon that fits into multiple composite shapes.

Number of Sides Number of Angles Interior Angle Measure
6 6 120°

Apart from common regular shapes like squares, triangles, and rectangles, hexagons have unique properties. A honeycomb cell consists of a regular hexagonal prism bounding two parallel planes. The ‘Six-Pointed Star‘ or ‘Star of David‘ is also a recognizable form composed entirely of equilateral triangles and regular hexagons.

It is astounding how bees create uniform six-sided cells with their little brains’ accuracy. According to an article published by Live Science in 2015, bees work collaboratively and use “wax scales extruded from glands on the underside of their abdomens” to build new cells.

An octagon has eight sides, making it the perfect shape for people who can’t decide if they’re a square or a circle.


This polygon has eight sides and eight angles. All its interior angles are equal, making each of them measure 135 degrees.

Octagons have a unique symmetry that makes it an ideal shape for architectural designs such as buildings and bridges. In addition, octagons can also be used in crafting tables, stop signs, and many other items we use in our everyday lives.

Octagons come in various forms such as regular, concave or even self-intersecting shapes. Regular ones are those where all the sides have equal length while concave octagons feature at least one interior angle measuring more than 180 degrees.

Pro Tip: When designing an octagonal object, be sure to keep the symmetry in mind to avoid it looking wonky. Whether it’s a triangle, square, or octagon, these polygons are all sides of the same shape.


After researching and analyzing polygons, it can be concluded that the number of sides a polygon has depends on its specific shape and type. Polygons can range from three sides to an infinite number of sides, depending on their classification. Regular polygons have equal sides and angles, while irregular polygons possess uneven measurements.

Polygons are commonly used in geometry and various other fields such as art, architecture, and engineering. For example, many buildings feature polygonal shapes in their design, like triangles or rectangles.

In addition to varying numbers of sides, polygons can also vary in other characteristics like area and perimeter. By understanding the properties of different types of polygons, we can gain insight into the world around us and advance our knowledge across various fields.

To further understand the nature of polygons, one can study Euclidean geometry or explore computer programming concepts like 2D graphics programming. Both options provide opportunities for hands-on learning and valuable insights into this fascinating mathematical topic.

Frequently Asked Questions

Q: What is a polygon?

A: A polygon is a closed figure made up of straight lines that connect at least three points.

Q: How many sides does a polygon have?

A: A polygon can have any number of sides but must have at least three.

Q: What do you call a polygon with three sides?

A: A polygon with three sides is called a triangle.

Q: What do you call a polygon with four sides?

A: A polygon with four sides is called a quadrilateral.

Q: Can a polygon have curved sides?

A: No, a polygon has straight sides.

Q: What is the sum of the interior angles of a polygon?

A: The sum of the interior angles of a polygon with n sides is (n-2) x 180 degrees.

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