What is a Perimeter?
The distance around a geometric shape
In math, the perimeter is the total length around the outside of a two-dimensional shape. You can think of it as the distance you would walk if you traced the entire edge of a figure.
To find the perimeter, we add up the lengths of all the sides of a shape. For example:
- A square with side lengths of 4 units has a perimeter of 4 + 4 + 4 + 4 = 16 units.
- A rectangle with a length of 6 units and a width of 3 units has a perimeter of 6 + 3 + 6 + 3 = 18 units.
Perimeter is used in real life when:
- Building a fence around a yard
- Putting a border around a picture or poster
- Measuring the edge of a table or field
When Do Students Learn About Perimeters?
Students begin learning about perimeter as they explore basic geometry and measurement.
Grades 2–3 – Introduction to Perimeter
Students learn to measure and add the sides of shapes to find the total distance around them.
Grades 4–5 – Applying Perimeter in Word Problems
Students solve real-world problems involving perimeter and start working with formulas for different shapes.
