perimeter and area
Walk round a shape to find its perimeter, cover it with unit squares to find its area, and see that shapes with the same area can have different perimeters.
- UK: Year 3
- France: grade 3
- Germany: grade 1
- Iran: grade 3
- Afghanistan: grade 2
- Syria: grade 3
- Palestine: grade 3
- Ukraine: grade 2
- Russia: grade 2
Guide
This studio matches perimeter and area in Year 3 to Year 5 (Iran grade 3, Afghanistan grades 2 to 4).
perimeter is the distance all the way round a shape: how far would an ant walk to get back where it started? It is measured in units of length. area is the amount of surface: how many unit squares cover the shape? It is measured in square units.
A common mistake is to count the squares along the edge to find the perimeter. A corner square has two sides on the edge, so this gives too small an answer. Ask your child to count the little sides on the boundary, not the squares.
Area of a rectangle = length × width. Cut an L-shape into two rectangles and add their areas. The last mission shows that the same area does not mean the same perimeter.