 # Perimeter of Triangle – Definition, Formulas, Example

## What is the Perimeter of a Triangle?

A perimeter refers to a path that encompasses a two-dimensional figure. Perimeter of triangle refers to the total distance around the outside of a triangle. Students can learn more about the perimeter of triangles here. ### Definition and Meaning of Perimeter of Triangle

First of all, the perimeter refers to a unit of measurement which facilitates the calculation of the distance around a closed figure. Perimeter of triangle refers to the sum of the lengths of the sides of a triangle. So, in order to find the perimeter of a triangle, one simply has to add the three sides together.

The calculation of the triangle’s perimeter takes place in a similar manner to any other polygon. Therefore, this calculation of a triangle’s perimeter can take place by adding together the length of each side. Consequently, the formula of the perimeter of the triangle would be a + b + c, where a, b, and c refer to the lengths of each side of a triangle.

### Equilateral and Isosceles Triangles

An equilateral triangle refers to a triangle where all three sides are equal. Consider an example of an equilateral triangle where all the sides are 2 inches in length. So, one must add 2 inches + 2 inches + 2 inches. This results in a total of 6 inches of perimeter.

An isosceles triangle refers to a triangle with at least two equal sides. However, the third side would have a different length. Consider an example, where two sides are 2 inches each, but the third side is three inches. Therefore, one would simply add all the sides, 2 inches + 2 inches + 3 inches. This would result in a perimeter of 7 inches.

### Obtuse, Acute and Right Triangles

When an individual has to deal with an obtuse, acute, or right triangle, the formula of perimeter remains the same as for any other triangle. An obtuse triangle refers to a triangle in which one of the angles is an obtuse angle. Furthermore, an obtuse angle is an angle that is more than 90 degrees but less than 180 degrees.

An acute triangle is one which has one angle which is less than 90 degrees. Moreover, this angle must be an internal angle. Finally, a right triangle is one which has one internal angle which is exactly 90 degrees.

To find the perimeter of any of these triangles, one simply has to add the lengths of all the three sides.

### Solved Question For You

Q1 Which of the following statements is not true when it comes to the perimeter of triangle?

1. Perimeter of the triangle refers to the total distance around the outside the triangle
2. Perimeter of the triangle refers to the sum of the lengths of the sides of a triangle
3. The formula of the perimeter of the triangle would be a + b + c
4. The perimeter of a triangle refers to the sum of its any two internal angles

A1 The correct option is D. Because “the perimeter of a triangle refers to the sum of its any two internal angles.” This is because the perimeter of a triangle has nothing to do with the angles of a triangle. Also, the perimeter of a triangle refers to the sum of the lengths of the sides of a triangle.

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