perimeter
C2Pronunciation
UK
- /pərˈɪmɪtə/
US
- /pərˈɪmətər/
Meanings
Noun
the outer boundary or edge of an area or place
the total distance around the outside of a shape or area
the outer boundary of an area being guarded or controlled
Beyond the definition
Imagine you're building a fence around your garden to keep the rabbits out. The total length of fencing you need—that's the perimeter! It's simply the distance all the way around the outside of any two-dimensional shape. Think of an ant walking along every edge of a square or rectangle, eventually returning to where it started—the total distance walked is the perimeter.
Perimeter isn't just for gardens and fences, though. Architects use it when designing buildings, and mapmakers use it to calculate distances on maps. It's calculated by adding up the lengths of all the sides. So a tiny postage stamp has a perimeter, as does a huge football field! Knowing the perimeter is useful when you need to frame a picture, trim fabric, or even figure out how much ribbon you'll need for a gift.
The perimeter refers to the total distance around the outside of a two-dimensional shape. It's like taking a walk along every edge and side until you end up back where you began. While we often think of it in terms of shapes like squares, rectangles, or triangles, anything with an outer boundary has a perimeter—even irregular shapes!
Calculating the perimeter is usually straightforward: simply add up the lengths of all the sides. For example, if a rectangle has sides measuring 5 cm and 8 cm, its perimeter would be . There are also formulas for specific shapes—like for a square—to make calculations even faster.
The concept of perimeter extends beyond geometry, too. You might hear it used metaphorically to describe the outer limits or boundaries of something else. For instance, "He stayed on the perimeter of the crowd," means he remained at the edge, observing from a distance.
In everyday life, understanding perimeter is practical for tasks like building projects (fencing, framing), crafting (trimming fabric, making borders), and even simple estimations. It's a fundamental concept in mathematics with real-world applications all around us. So next time you see a shape, remember to think about the distance it takes to go all the way around—that's its perimeter!
Examples
- 1
Playground
The children ran around the perimeter of the playground.
- 2
Garden boundary
A low fence marks the perimeter of the garden.
- 3
Police response
Police set up a perimeter around the building after the alarm went off.
- 4
Security patrol
Guards walked the perimeter of the camp every hour.
More examplesFewer examples
- 5
Geometry
To find the perimeter of a rectangle, add the lengths of all four sides.
- 6
Site security
The team was told to secure the perimeter before anyone entered the site.
- Phrasesecure the perimeter
make sure no one can enter or leave an area
See also
Forms and spellings
2 forms open this card.
Main spelling
- perimeternoun
Forms
- perimeterspluralnoun