### Mensuration-Revision Notes

CBSE Class 6 Mathematics
Revision Notes
CHAPTER – 10
Mensuration

• 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 $\frac{1}{2}$sq units.
• Area of a rectangle = length × breadth
• Area of a square = side × side