Perimeter of a triangle, step by step
A triangle's perimeter is the distance around it: add the three sides.
The question
cm
Perimeter of a 13-13-20 triangle
sides:131320
sides:131320
sides:131320
13 + 13 + 20=46 cm
- Perimeter is the distance round the OUTSIDE — the length of the fence, not the size of the field. That is the whole difference between this and area, and it is where the usual wrong answer comes from.
- So there is nothing to work out — just walk round the edge and add: 13 + 13 + 20.
- 13 + 13 + 20 = 46 cm. Note the unit: cm, not square cm — a fence is a length, and a length never gets squared.
How it works.
- 01
Perimeter is the distance round the OUTSIDE — the length of the fence, not the size of the field. That is the whole difference between this and area, and it is where the usual wrong answer comes from.
- 02
So there is nothing to work out — just walk round the edge and add: 13 + 13 + 20.
- 03
13 + 13 + 20 = 46 cm. Note the unit: cm, not square cm — a fence is a length, and a length never gets squared.