BrightChamps Logo
Login
Creative Math Ideas Image
Live Math Learners Count Icon105 Learners

Last updated on July 29th, 2025

Math Whiteboard Illustration

Perimeter of Polygon

Professor Greenline Explaining Math Concepts

The perimeter of a shape is the total length of its boundary. The sum of all the sides is called the perimeter of a polygon. Perimeter is also used for fencing a property, sewing, and more. In this topic, we will learn about the perimeter of a polygon.

Perimeter of Polygon for Filipino Students
Professor Greenline from BrightChamps

What is the Perimeter of a Polygon?

The perimeter of a polygon is the total length of its sides. By adding the length of all sides, we get the perimeter of the shape. The formula for the perimeter of a polygon depends on the number of sides. For instance, if a pentagon has sides of lengths 5, 7, 8, 6, and 4, then its perimeter is P = 5 + 7 + 8 + 6 + 4 = 30.

Professor Greenline from BrightChamps

Formula for Perimeter of Polygon

Let’s consider another example of a hexagon with sides of lengths 3, 5, 6, 7, 4, and 2. So the perimeter of the hexagon will be: P = 3 + 5 + 6 + 7 + 4 + 2 = 27.

Professor Greenline from BrightChamps

How to Calculate the Perimeter of a Polygon

To find the perimeter of a polygon, we just need to apply the given formula and sum all the sides of the polygon. For instance, a given octagon has sides of lengths 4, 4, 4, 4, 4, 4, 4, and 4. Perimeter = sum of all sides = 4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 = 32 units. Example Problem on Perimeter of Polygon - For finding the perimeter of a polygon, we use the formula, P = sum of all sides. For example, let’s say a quadrilateral has sides: 5 cm, 4 cm, 3 cm, and 2 cm. Now, the perimeter = sum of all sides = 5 + 4 + 3 + 2 = 14 cm. Therefore, the perimeter of the quadrilateral is 14 cm.

Professor Greenline from BrightChamps

Tips and Tricks for Perimeter of Polygon

Learning some tips and tricks makes it easier for children to calculate the perimeter of polygons. Here are some tips and tricks given below: Always remember that a polygon's perimeter is simply the sum of the sides of the shape. For that, use the formula, P = sum of all sides. Calculating the perimeter of a polygon starts by determining the length of each side using the distance formula. The distance formula is: Distance = √((x2-x1)² + (y2-y1)²). Here, (x1, y1) and (x2, y2) indicate the positions of two points that make up a polygon’s side. They can be found by adding the lengths of all sides after they are calculated. To reduce confusion, specifically arrange the indicated side lengths if you need the perimeter of a group of polygons. After that, apply the formula to each polygon. To avoid mistakes when adding the perimeter, make sure the side lengths are precise and constant for common uses like gardening and architecture. If you are given the semi-perimeter, which is half the perimeter, you can multiply it by 2 to determine the full perimeter. Area-related calculations, like Heron’s formula, often use the semi-perimeter.

Max Pointing Out Common Math Mistakes

Common Mistakes and How to Avoid Them in Perimeter of Polygon

Did you know that while working with the perimeter of a polygon, children might encounter some errors or difficulties? We have many solutions to resolve these problems. Here are some given below:

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Incorrectly using the Pythagorean theorem (a² + b² = c²) for polygons that do not form right-angled triangles.

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Remember that only right-angled triangles can use the Pythagorean theorem. The lengths of all the sides of other polygon types should be summed up to find the perimeter.

Mistake 2

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Students may confuse the concepts of area and perimeter, leading to incorrect calculations.

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

It is important to note that the perimeter, calculated in linear units, is the total length of the polygon’s sides, while the area, in square units, represents the space inside the polygon.

Mistake 3

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Assuming that every polygon has equal sides, which results in inaccurate calculations.

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

A scalene polygon has all sides of different lengths. Always be careful about the type of polygon to ensure accurate calculations.

Mistake 4

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Using the wrong values for the length of the sides, misreading a problem, or mislabeling the sides.

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Double-check the problem and ensure that you're using the correct lengths for your polygon.

Mistake 5

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Misunderstanding or misidentifying the side lengths that are given in a problem outline.

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

Before starting the calculations, make sure that you understand the problem and, if it's possible, try to draw the polygon to accurately identify the side lengths.

arrow-right
Max from BrightChamps Saying "Hey"
Hey!

Perimeter of Polygon Examples

Ray, the Character from BrightChamps Explaining Math Concepts
Max, the Girl Character from BrightChamps

Problem 1

A pentagon-shaped garden has a perimeter of 60 meters, and four sides measure 12 meters each. To find out the missing side of the garden, subtract the sum of the known sides from the total perimeter.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"
Okay, lets begin

Length of the missing side = 12 meters.

Explanation

Let ‘s’ be the side of the missing side. And the given perimeter = 60 meters. Length of the four equal sides = 12 meters. Perimeter of pentagon = sum of lengths of five sides. 60 = 12 + 12 + 12 + 12 + s 60 = 48 + s s = 60 – 48 = 12 s = 12 Therefore, the missing side is 12 meters.

Max from BrightChamps Praising Clear Math Explanations
Well explained 👍
Max, the Girl Character from BrightChamps

Problem 2

A wire with a perimeter of 360 inches is reshaped into a square. Find the length of each side of the square and divide the total length by 4.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"
Okay, lets begin

90 inches

Explanation

Given that the perimeter of the wire is equal to the total length of the wire and this wire is reshaped into a square, here is the solution: Perimeter of the wire = Total length of the wire Length of the wire used = Perimeter of the square formed Perimeter of a square = 4 × s 360 = 4 × s 360 ÷ 4 = 90 s = 90 Therefore, the length of each side of the square is 90 inches.

Max from BrightChamps Praising Clear Math Explanations
Well explained 👍
Max, the Girl Character from BrightChamps

Problem 3

Find the perimeter of a regular hexagon whose sides are 9 cm.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"
Okay, lets begin

54 cm

Explanation

Perimeter of hexagon = 6 × side length P = 6 × 9 = 54 Therefore, the perimeter of the hexagon is 54 cm.

Max from BrightChamps Praising Clear Math Explanations
Well explained 👍
Max, the Girl Character from BrightChamps

Problem 4

Jake is designing a hexagonal flower bed in his backyard. He measures the six sides of the bed: Side A = 3 meters Side B = 5 meters Side C = 4 meters Side D = 3 meters Side E = 5 meters Side F = 4 meters How much fencing should Jake buy to go around the edge of the flower bed?

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"
Okay, lets begin

Jake will need 24 meters of fencing to go around the flower bed.

Explanation

The perimeter of the hexagon is the sum of all six sides. Using the formula: P = a + b + c + d + e + f P = 3 + 5 + 4 + 3 + 5 + 4 = 24 meters.

Max from BrightChamps Praising Clear Math Explanations
Well explained 👍
Max, the Girl Character from BrightChamps

Problem 5

Find the perimeter of a scalene polygon with sides 11, 9, and 6 meters.

Ray, the Boy Character from BrightChamps Saying "Let’s Begin"
Okay, lets begin

Perimeter = 11 + 9 + 6 = 26 meters.

Explanation

Each side of the scalene polygon has a different length. The entire distance around the polygon is calculated as 26 meters by summing the lengths of the three sides.

Max from BrightChamps Praising Clear Math Explanations
Well explained 👍
Ray Thinking Deeply About Math Problems

FAQs on Perimeter of Polygon

1.Evaluate the perimeter of a quadrilateral if its sides are 2 cm, 7 cm, 5 cm, and 8 cm.

Perimeter of quadrilateral = sum of all sides, hence P = 2 + 7 + 5 + 8 = 22 cm.

Math FAQ Answers Dropdown Arrow

2.What is meant by a polygon’s perimeter?

The total length around a polygon’s sides is its perimeter. In other words, the perimeter of a polygon is the total length of its sides.

Math FAQ Answers Dropdown Arrow

3.What are the types of polygons?

Polygons can be classified by the number of sides: triangle (3 sides), quadrilateral (4 sides), pentagon (5 sides), hexagon (6 sides), heptagon (7 sides), and more.

Math FAQ Answers Dropdown Arrow

4.Which polygon has no equal sides?

A scalene polygon is a polygon with no equal sides. All sides of a scalene polygon are different.

Math FAQ Answers Dropdown Arrow

5.Which polygon has equal sides and angles?

A regular polygon has all sides and angles equal. Examples include an equilateral triangle and a square.

Math FAQ Answers Dropdown Arrow
Professor Greenline from BrightChamps

Important Glossaries for Perimeter of Polygon

Perimeter: The total length of the sides of a shape. Polygon: A closed figure with three or more straight sides. Regular polygon: A polygon with all sides and angles equal. Scalene polygon: A polygon with all sides of different lengths. Formula of perimeter: The mathematical expression used to calculate the perimeter of a polygon is the sum of its side lengths.

Math Teacher Background Image
Math Teacher Image

Seyed Ali Fathima S

About the Author

Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.

Max, the Girl Character from BrightChamps

Fun Fact

: She has songs for each table which helps her to remember the tables

INDONESIA - Axa Tower 45th floor, JL prof. Dr Satrio Kav. 18, Kel. Karet Kuningan, Kec. Setiabudi, Kota Adm. Jakarta Selatan, Prov. DKI Jakarta
INDIA - H.No. 8-2-699/1, SyNo. 346, Rd No. 12, Banjara Hills, Hyderabad, Telangana - 500034
SINGAPORE - 60 Paya Lebar Road #05-16, Paya Lebar Square, Singapore (409051)
USA - 251, Little Falls Drive, Wilmington, Delaware 19808
VIETNAM (Office 1) - Hung Vuong Building, 670 Ba Thang Hai, ward 14, district 10, Ho Chi Minh City
VIETNAM (Office 2) - 143 Nguyễn Thị Thập, Khu đô thị Him Lam, Quận 7, Thành phố Hồ Chí Minh 700000, Vietnam
UAE - BrightChamps, 8W building 5th Floor, DAFZ, Dubai, United Arab Emirates
UK - Ground floor, Redwood House, Brotherswood Court, Almondsbury Business Park, Bristol, BS32 4QW, United Kingdom