Shapes

5. Perimeter and area

• The perimeter is the distance all the way around the
  outside of a 2D shape.
• To work out the perimeter, add up the lengths of all
  the sides.
  
• The area of a 2D shape is the amount of surface
  it covers.
• The units for area are cm² (square centimetres),
  m² (square metres) or km² (square kilometres).
• To work out the area of a rectangle, multiply
  its length (the longer side) by its width
  (the shorter side).