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## 3rd grade

### Course: 3rd grade > Unit 11

Lesson 4: Comparing area and perimeter# Perimeter: FAQ

Frequently asked questions about finding the perimeter of shapes.

## What is perimeter?

Perimeter is the total distance around the outside of a shape.

## How do I find the perimeter of a polygon?

To find the perimeter of a polygon, we add up the lengths of all the sides.

## What's the difference between area and perimeter?

Area is the amount of space inside a shape, while perimeter is the distance around the outside of a shape.

## What if I don't know the length of one of the sides?

Sometimes we might need to use clues from the shape to figure out the missing side length. For example, if we know that a square has a perimeter of 16, we can divide by 4 to find that each side must be 4 units long.

## When do people use perimeter in the real world?

Perimeter is often used in construction and landscaping. For example, we might use perimeter to figure out how much fencing we need to go around a garden, or how much trim we need to go around a window.

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