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:

1. Identify the length of each side of the triangle. The sides can be represented as a, b, and c.
2. 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.

1. Identify the lengths of the sides: a = 5 cm, b = 7 cm, and c = 9 cm.
2. 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.

1. Identify the lengths of the sides: a = 12 cm, b = 16 cm, and c = 20 cm.
2. 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.