M3.6.2 For the adult
Perimeter
How much fence do I need to go all the way round my garden?
What this chapter teaches
The perimeter is the distance all the way round a shape. You add every side. When a side is missing, take the sides you know away from the perimeter, or work the side out from the opposite edge.
Three questions to ask
There is no one right wording. Listen for the idea.
- How would you find the length of a fence round a rectangular field?
- Why is the perimeter of a rectangle not just its length plus its width?
- A square has a perimeter of 20 cm. How long is each side?
After the chapter, the learner can
- Find the perimeter of a shape with straight sides
- Find a missing side when you know the perimeter
What they copy into their notebook
Perimeter is the distance all the way round. Add every side and write the unit. Rectangle: 2 × (length + width). Square: 4 × side. Missing side: perimeter minus the sides you know.