# How to Calculate the Perimeter of a Triangle

## Perimeter of Triangle Calculator

*Use this calculator to verify your answer only, don’t make it a habit. Scroll down to learn the calculation method*

## Let’s Learn the Calculation Method

To calculate the perimeter of a triangle, you simply add the lengths of all three sides together. Here’s a step-by-step guide along with two examples:

Step-by-step guide:

- Identify the length of each side of the triangle. The sides can be represented as a, b, and c.
- Add the lengths of the three sides together to find the perimeter.

Formula: Perimeter (P) = a + b + c

**Example 1:**

Suppose you have a triangle with side lengths of 5 cm, 7 cm, and 9 cm.

- Identify the lengths of the sides: a = 5 cm, b = 7 cm, and c = 9 cm.
- Add the lengths together: P = a + b + c = 5 + 7 + 9 = 21 cm.

So, the perimeter of this triangle is 21 cm.

**Example 2:**

Let’s consider a triangle with side lengths of 12 cm, 16 cm, and 20 cm.

- Identify the lengths of the sides: a = 12 cm, b = 16 cm, and c = 20 cm.
- Add the lengths together: P = a + b + c = 12 + 16 + 20 = 48 cm.

In this case, the perimeter of the triangle is 48 cm.

## Example 3:

How about when you have a weirdly shaped triangle?

Well, the solution is the same. Add up all the side’s values.

So Perimeter = 5cm + 6cm + 3cm + 4 cm

P = 18cm is the answer.