Mensuration-Revision Notes

CBSE Class 6 Mathematics
Revision Notes

  • Perimeter is the distance covered along the boundary forming a closed figure when you go round the figure once.
    (a) Perimeter of a rectangle = 2 × (length + breadth)
    (b) Perimeter of a square = 4 × length of its side
    (c) Perimeter of an equilateral triangle = 3 × length of a side
    (d) Perimeter of a regular pentagon has five equal sides = 5 × length of a sides
  • Figures in which all sides and angles are equal are called regular closed figures.
  • The amount of surface enclosed by a closed figure is called its area.
  • To calculate the area of a figure using a squared paper, the following conventions are adopted :
    (a) Ignore portions of the area that are less than half a square.
    (b) If more than half a square is in a region. Count it as one square
    (c) If exactly half the square is counted, take its area as 12sq units.
  • Area of a rectangle = length × breadth
  • Area of a square = side × side