110 LearnersLast updated on August 5th, 2025
Perimeter of Equilateral Triangle
The perimeter of a shape is the total length of its boundary. The sum of all three equal sides is called the perimeter of an equilateral triangle. Perimeter is also used for fencing a property, sewing, and more. In this topic, we will learn about the perimeter of an equilateral triangle.
What is the Perimeter of an Equilateral Triangle?
The perimeter of an equilateral triangle is the total length of its three equal sides. By adding the length of all three sides, we get the perimeter of the shape. The formula for the perimeter of an equilateral triangle is π· = 3π, where π is the length of one side of the triangle. For instance, if an equilateral triangle has sides, π = 5, then its perimeter is π· = 3 Γ 5 = 15.
Formula for Perimeter of Equilateral Triangle - π· = 3π.
Letβs consider another example of an equilateral triangle with side length π = 7. So the perimeter of the triangle will be: π· = 3 Γ π = 3 Γ 7 = 21.
How to Calculate the Perimeter of an Equilateral Triangle
To find the perimeter of an equilateral triangle, we just need to apply the given formula and multiply the side length by 3. For instance, a given equilateral triangle has the side π = 9. Perimeter = 3 Γ π = 3 Γ 9 = 27 cm. Example Problem on Perimeter of Equilateral Triangle - For finding the perimeter of an equilateral triangle, we use the formula, π· = 3π. For example, letβs say π = 6 cm. Now, the perimeter = 3 Γ 6 = 18 cm. Therefore, the perimeter of the triangle is 18 cm.
Tips and Tricks for Perimeter of Equilateral Triangle
Learning some tips and tricks makes it easier for children to calculate the perimeter of equilateral triangles. Here are some tips and tricks given below: Always remember that an equilateral triangle's perimeter is simply three times the length of one side. For that, use the formula, π· = 3π. Calculating the perimeter of an equilateral triangle starts by determining the length of one side. If given coordinates, use the distance formula: Distance = β((x2-x1)Β² + (y2-y1)Β²). To reduce confusion, specifically arrange the indicated side lengths if you need the perimeter of multiple triangles. After that, apply the formula to each triangle. To avoid mistakes when calculating the perimeter, make sure the side lengths are precise and consistent, especially for applications like construction or design. If you are given the semi-perimeter, which is half the perimeter, you can multiply it by 2 to determine the full perimeter.
Common Mistakes and How to Avoid Them in Perimeter of Equilateral Triangle
Did you know that while working with the perimeter of an equilateral triangle, children might encounter some errors or difficulties? We have many solutions to resolve these problems. Here are some given below:
Mistake 1
Confusing the formula for equilateral triangles with other triangle types.
Remember that the formula π· = 3π is specific to equilateral triangles. For other triangles, sum the lengths of all sides for the perimeter.
Mistake 2
Mixing up concepts of area and perimeter, leading to incorrect calculations.
It is important to note that the perimeter, calculated in linear units, is the total length of the triangleβs sides, while the area, in square units, represents the space inside the triangle.
Mistake 3
Incorrectly assuming all triangles are equilateral, which results in inaccurate calculations.
Ensure you know the type of triangle you're dealing with. An equilateral triangle has all sides equal, unlike scalene or isosceles triangles.
Mistake 4
Using the wrong values for the length of the sides, misreading a problem, or mislabeling the sides.
Double-check the problem and ensure that you're using the correct lengths for your triangle.
Mistake 5
Misunderstanding or misidentifying the side lengths that are given in a problem outline.
Before starting the calculations, make sure that you understand the problem and, if it's possible, try to draw a triangle to accurately identify the side lengths.
Perimeter of Equilateral Triangle Examples
Problem 1
An equilateral triangular park has a perimeter of 60 meters. What is the length of each side of the park?
Each side is 20 meters long.
Explanation
Let βπβ be the length of each side of the park. The given perimeter = 60 meters. Perimeter of equilateral triangle = 3π. 60 = 3π π = 60 Γ· 3 = 20 Therefore, each side is 20 meters long.
Problem 2
A piece of string with a perimeter of 150 inches is reshaped into an equilateral triangle. Find the length of each side of the triangle.
50 inches
Explanation
Given that the perimeter of the string is equal to the perimeter of the equilateral triangle, here is the solution: Perimeter of an equilateral triangle = 3π 150 = 3π 150 Γ· 3 = 50 π = 50 Therefore, the length of each side of the triangle is 50 inches.
Problem 3
Find the perimeter of an equilateral triangle whose sides are 12 cm.
36 cm
Explanation
Perimeter of triangle = 3π π· = 3 Γ 12 = 36 Therefore, the perimeter of the triangle is 36 cm.
Problem 4
Alex is using a piece of wood to create an equilateral triangular frame. The length of each side of the frame is 15 meters. How much wood does he need in total?
Alex will need 45 meters of wood.
Explanation
The perimeter of an equilateral triangle is the sum of all three equal sides. Using the formula: π· = 3π π· = 3 Γ 15 = 45 meters.
Problem 5
Determine the perimeter of an equilateral triangular garden where each side measures 18 meters.
The perimeter is 54 meters.
Explanation
The perimeter of an equilateral triangle is calculated by summing the lengths of its sides. π· = 3π π· = 3 Γ 18 = 54 meters.
FAQs on Perimeter of Equilateral Triangle
1.Evaluate the triangleβs perimeter if its sides are 9 cm.
2.What is meant by an equilateral triangleβs perimeter?
3.What is the formula for the perimeter of an equilateral triangle?
4.How do you find the perimeter of an equilateral triangle if the side length is known?
5.Can the perimeter of an equilateral triangle be calculated if only the semi-perimeter is given?
Important Glossaries for Perimeter of Equilateral Triangle
Perimeter: The total length of the sides of a shape. Equilateral Triangle: A polygon with three equal sides and three equal angles. Formula of Perimeter: The mathematical expression used to calculate the perimeter of an equilateral triangle is π· = 3π. Semi-perimeter: Half the perimeter of a triangle. Distance Formula: A formula used to calculate the distance between two points in a plane.
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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.
Fun Fact
: She has songs for each table which helps her to remember the tables
