Know that the perimeter is the distance around a 2D shape | Maths

Starter quiz

Which of these shapes has string around its outline?
- a ✓
- b
- c
Which of these symbols means ‘greater than’?
- <
- > ✓
- =
Which of these shapes are 2D shapes?
Is this a 2D shape? Select the best answer and reason.
- Yes. It is a triangle.
- No. It is a 3D shape.
- No. It is not closed. ✓
Number rods have been used to make polygons. Which ones are polygons?
- A ✓
- B
- C ✓
Which 2D shapes can you see on this football pitch?
- Circle ✓
- Semi-circle ✓
- Square
- Rectangle ✓
- Hexagon

Exit quiz

Which of these is the definition of perimeter?
- A straight line.
- The distance around the outside of a 2D shape. ✓
- The space inside a 2D shape.
Which of these are true of perimeter?
- It does not matter if you go inside or outside the lines when finding perimeter.
- You can start at any point in a shape, but you must finish at the same point. ✓
- You must cover the whole of the outside of the shape. ✓
- It does not matter if you go clockwise or anti-clockwise when finding perimeter. ✓
Which of these shows the perimeter of the triangle?
- a
- b ✓
- c
- d
In terms of perimeter, which of the statements are true of this image?
- Shape A and B have equal perimeter.
- The perimeter of Shape A is greater than Shape B.
- The perimeter of Shape A is less than Shape B. ✓
- The perimeter of Shape B is less than Shape A.
- The perimeter of Shape B is greater than Shape A. ✓
In terms of perimeter, which of the statements are true of this image?
- Shape A and B have equal perimeter.
- The perimeter of Shape A is greater than Shape B. ✓
- The perimeter of Shape A is less than Shape B.
- The perimeter of Shape B is le less than Shape A. ✓
- The perimeter of Shape B is greater than Shape A.
Order the shapes according to their perimeter, starting with the shortest perimeter.
- 1
  
  ⇔
  
  d
- 2
  
  ⇔
  
  a
- 3
  
  ⇔
  
  b
- 4
  
  ⇔
  
  c

Worksheet

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Presentation

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Lesson Details

Key learning points

Perimeter is a measurement of length.
Perimeter is the distance around a 2D shape.

Common misconception

When finding the perimeter of a shape, pupils may count one side twice, or not count one of the sides.

Examples and non-examples of perimeter are given but encourage pupils to mark a 'start point' when they find the perimeter of a shape, so that they know where to end.

Keywords

Perimeter - The distance around a 2D shape.