Perimeter of Equilateral Triangle
Perimeter of an equilateral triangle is the distance around the sides of a threesided polygon which is triangular and also called a trigon. Perimeter is always represented as the same measurement unit according to the unit used for the sides. In geometry, an equilateral triangle is a triangle with all three sides equal. In the word equilateral, "equi" refers to equivalent and "lateral" refers to sides. In this article, we will learn about what is the perimeter of an equilateral triangle and how to find the perimeter of an equilateral triangle with the help of solved examples.
What is the Perimeter of Equilateral Triangle?
A trigon or a triangular shape is considered to be equilateral if it has the following basic properties:
 all three sides are equal
 all three angles are equal (∠P, ∠Q and, ∠R = 60°)
As per the properties of the equilateral triangle, the perimeter of the equilateral triangle is the sum of three sides. Thus, the perimeter of equilateral triangle = 3a (where a is the side of an equilateral triangle)
In the given figure the sides of equilateral triangle PQR are equal i.e. PQ = QR = RP = a units.
Few other formulas for the given equilateral triangle are:
 The formula for Semi Perimeter of Equilateral Triangle = (a + a + a)/2 = 3a/2
 The formula for Height of an Equilateral Triangle = √3a/ 2
How to Find Perimeter of an Equilateral Triangle?
We just read about the perimeter of an equilateral triangle, that is 3a, here a = side of an equilateral triangle. Now let us learn how to apply the formula of the perimeter of an equilateral triangle. Let's read and understand the practical illustration given below.
Example: Find the perimeter and semiperimeter of an equilateral triangle with side 9 units.
Solution:
Given: Side of equilateral triangle = a = 9 units. The perimeter of an equilateral triangle = 3a. Put the value of a = 9 in the formula = 3 × 9 = 27 units
SemiPerimeter of an equilateral triangle = 3a/2. Put the value of a = 9 in the formula = (3 × 9)/2 = 27/2 = 13.5 units
Note: SemiPerimeter of an equilateral triangle is half of the perimeter of an equilateral triangle
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Solved Examples on Perimeter of Equilateral Triangle

Example 1: Calculate the perimeter of an equilateral triangle whose each side is 10 inches.
Solution:
Perimeter of equilateral triangle = 3a, where a is the side. Given, a = 10 inches. Thus, perimeter = 3 × 10 = 30 inches. Therefore, the perimeter of equilateral triangle is 30 inches.

Example 2: What is the perimeter of an equilateral triangle with each side measuring 30 inches. Can you find the height of this equilateral triangle?
Solution:
Perimeter of equilateral triangle = 3a, where a is the side. Given a = 30 inches. Thus, the perimeter of the equilateral triangle = 3 × 30 = 90 inches, and the height of the equilateral triangle = √3a/2. Therefore, the height of the equilateral triangle is = (√3 × 30)/2 = 15√3 inches.

Example 3: What are the perimeter and semi perimeter of an equilateral triangle with side measurement as 12 units.
Solution:
Perimeter of equilateral triangle = 3a and semiperimeter of an equilateral triangle = 3a/ 2, where a is the side. Given a = 12 units. Therefore, the perimeter of equilateral triangle = 3 × 12 = 36 units and Semiperimeter of an equilateral triangle = 36/2 = 18 units.
FAQs on Perimeter of Equilateral Triangle
What do you Mean by Perimeter of Equilateral Triangle?
The sum of the distance around the sides of a threesided polygon which is triangular in shape and also called trigon is termed as the perimeter of equilateral triangle. It is given as (3 × side of equilateral triangle).
Is an Equilateral Triangle a regular polygon? Why?
Yes, an equilateral triangle is considered as a regular polygon because:
 It is a closed triangular shape.
 It is a regular triangle with three equal angles.
 It has three equal sides.
How to Find the Perimeter of Equilateral Triangle?
To find the perimeter of equilateral triangle, observe the given data in the question, such as the side of equilateral triangle. Put the value of side in the formula of the perimeter of equilateral triangle (3 × sides of equilateral triangle) and solve.
How many Sides does an Equilateral Triangle have?
An equilateral triangle has three sides. The measurements of each side are equal.
What is the Sum of all the Angles of an Equilateral Triangle?
The sum of all the angles of an equilateral triangle is equal to 180 degrees. Each angle measures 60°. Accordingly, 60°+ 60°+ 60° =180 degrees
How many Angles does an Equilateral Triangle have?
An equilateral triangle has three angles. The measurements of each angle are the same. All the angles are equal to 60 degrees. The sum of angles is equal to 180 degrees.