How to Find Perimeter of a Triangle

Have you ever noticed why engineers measure the land before starting construction? The answer is to find the perimeter. You may be thinking that finding the parameter of a plain shape may be easy, but how to find perimeter of a triangle. It is easy if you use the perimeter of triangle formula.

In this blog, you will learn what a perimeter is and how to calculate the perimeter of a triangle with different sides using the perimeter formula for triangle.

Perimeter

The perimeter may have different meanings across different fields. In mathematical terms, the perimeter is defined as the total distance of the outer boundary of any shape. It is calculated by adding the length of all sides together. 

Perimeter of Triangle

A triangle is an important shape in geometry. A triangle contains three sides. The perimeter of triangle is the total length of its outer boundary. There are different types of triangles based on the shape. So, the formula to find perimeter of a triangle will be different. 

How to Find the Perimeter of a Triangle

Finding the perimeter of a triangle is fun. It is like you started measuring from one vertex of a triangle and reached the same point after measuring the total length around it. 

To find the perimeter of the triangle, we just need to add the length of all three sides of a triangle. 

Formula for Perimeter of a Triangle

The calculation of the perimeter of triangles involves a simple step of adding all the sides of a triangle. A general formula for perimeter of a triangle is given as;

Where, a , b , and  c  represent the three sides of a triangle. The formula can also be written as; 

Perimeter = sum of the three sides

Perimeter of Triangles of Different Types

Triangles are of different types based on the length of their sides. Here, you will learn to find the perimeter of triangles with different sides. 

Perimeter of Scalene Triangle 

A triangle with three sides of different lengths is known as the scalene triangle. The Perimeter of scalene triangle is calculated by adding the length of all sides with different lengths.  

The formula of perimeter of a scalene triangle is given as;

Where, a, b, and c are three unequal sides. 

Example: 

Find the perimeter of a scalene triangle with the sides 5cm, 7cm, and 8cm.

As we know the formula to find the perimeter of an scalene triangle is given as;

Putting value in the formula.

Perimeter of an Isosceles Triangle

An isosceles triangle is a triangle which has two equal sides. The Perimeter of an Isosceles triangle can be found by adding two equal and one unequal side. 

The formula for perimeter of an isosceles triangle is given as;

Where two sides, i.e., a and c, are equal.

Example: find the perimeter of a isosceles triangle with the two equal sides of 6 cm and one side with 5cm.

The formula for perimeter of an isosceles triangle is 

Perimeter of the Equilateral Triangle

A triangle with all sides equal is known as the equilateral triangle. The Perimeter of the equilateral triangle is calculated by adding the length of all sides together. 

The formula of equilateral triangle perimeter is given as;

In which, a, b and c are the sides of an equilateral triangle.

As we know, the three sides of an equilateral triangle are equal, then it can be written as;

Example: 

Find the perimeter of the equilateral triangle with a side of 7 cm each. 

Formula for equilateral triangle perimeter is;

Perimeter of Right Triangle

A right triangle is a triangle whose one angle is a right angle or has one internal angle equal to 90 degrees. The perimeter of right triangle is found by adding all its sides. A perimeter formula for a right triangle is given as;

For a right-angled triangle, Pythagoras' theorem can be used to find any missing side. 

Example: 

Find the perimeter of a right triangle that has sides of 10 cm, 8cm, and 12 cm.

The formula to find the perimeter of a right triangle is given as;

Put the value in the formula 

Perimeter of an Isosceles Right Triangle

An isosceles right triangle has two equal sides and two of the angles are equal. An isosceles right triangle perimeter formula is written as;

In which, l is the length of two equal sides and h is the length of the hypotenuse. 

Example: 

Find the perimeter of the isosceles right triangle with two sides of 12 cm each and hypotenuse 6 cm. 

An isosceles right triangle perimeter formula is written as;

So, we learned how to find perimeter of a triangle by using perimeter of triangle formula. You can practice it on your own. If you want to learn math and mathematical concepts easily, you can hire our expert tutors.