clearly. After introduction of the idea, sufficient practice must be given to the child
to memorize all the formulae relating to area of different geometrical figures.
Memorisation is necessary but mere rote memory will not least long. The child must
be helped to understand the different parts of the formulae.
- Mensuration
The branch of mathematics which deals with the measure of lengths, angles, areas,
perimeters and volumes of plane and solid figures is called as mensuration.
- Area of rectangular pathways
In mensuration, finding the area of pathways and finding the area excluding the
pathways finds a prominent place. Say for instance, if a garden is in the shape of a
rectangle with pathways on all the four sides of the rectangle and if the area of the
garden excluding the pathway is to be found out, the formula should be used:
Area of the garden = Area of the outer rectangle – Area of the pathway
A cutout in the form of a rectangle with a rectangular pathway inside may be provided
to the child to understand the idea and when the child is clear with the idea, he/she
may be taught the method of finding the area of the rectangular pathway. The braille
cells of the braille slate may also be used to explain this concept.
- Area of a square
Area of a square refers to the amount of surface enclosed by the square.
Area of a square = side ×^ side
In symbols, A = a ×^ a
=a^2 square units
Here, the symbol A denotes the area and ‘a’ denotes the measure of a side.
