Illustrated · 1 min
Perimeter is the length of space around an object. So let's say we have this polygon:
So we can conclude that the perimeter of this triangle is 10 units because 3+3+4=10.
Find your level
The problems run from approachable to very hard, and each is rated by how often real students solve it, so you can pick your next step. These are real problems from the AMC 8, AMC 10, AMC 12 and AIME, the national math competitions for middle and high school students, each with a worked solution on LIVE by Po-Shen Loh.
- Perimeter problems 48 from AMC 8, AMC 10, AMC 12, AIME
Interactive · 1 question
Perimeter: an example
All shapes in 2-dimension have perimeters. The perimeter of a shape is the sum length of all its sides.
The triangle has 3 sides, they have lengths of 2.5, 5 and 5.5. The perimeter of this triangle is the sum length of all these sides: In the example above, the unit of length is not specified--so we only worry about the numbers.
Perimeter of a rectangle
Julia's family recently moved into a new house and she finally has her own room! She drew a rough plan for her room. She wants to line the four walls with fairy lights--roughly how much does she need to buy (in length)?
The question is essentially asking for the perimeter of the rectangle given above. Can you calculate it?
Roughly how much fairy lights should Julia buy?