---
title: "Perimeter of a Triangle"
description: "Learning video: We add all 3 sides: 4 plus 5 plus 6 centimeters. The perimeter is 15 centimeters. All 3 sides are 7 cm long. What is the perimeter?"
canonical: "https://www.mathapex.app/en/math-stories/geometry/perimeter-of-a-triangle/"
language: "en"
video: "https://www.mathapex.app/media/stories/videos/en/perimeter-of-a-triangle.72f72510.mp4"
duration: "PT29S"
---

# Perimeter of a Triangle

Learning video 65 · Geometry · Grade 4 · 0:29

## Read the story

For a triangle, too, the perimeter is the way all around.

We add all 3 sides: 4 plus 5 plus 6 centimeters.

The perimeter is 15 centimeters.

**All 3 sides are 7 cm long. What is the perimeter?**

## Answer and working

Correct! 3 times 7 is 21 centimeters.

`3 × 7 = 21`