Page 106 - Maths Skill - 6

104 Maths

AREA OF A SQUARE
We know that a square is a special rectangle in which all of its sides are equal. So, the same area formula can be
applied to calculate the area of a square.
So, area of a square = (length × length) square units
2
= (length) square units
2
= (side) square units
\ Area of square = (side) square units
2

From the above relation, we have

Side =Areaofthe square

AREA OF TRIANGLE
If you want to know the area of triangle with the help of rectangle then first of all draw a rectangle on a piece of
paper and also draw its diagonals. Cut the rectangle along that diagonal and get two triangles.
Now, according to figure
A B
Area of rectangle ABCD = Area of triangle (ABD) + Area of triangle (DCB)

Area of rectangle = 2 × Area of triangle

Note : These two triangles over lap each other exactly D C
So, Area of ∆ ABD = Area of ∆ DCB
Now, Calculate the area of triangle using the square grid, if each square has side of 1 cm

Alternative Approach

We know that
1
Area of triangle = × Base × height
2
In this triangle ⇐ Base = 4, height = 3
1
Area of triangle = × Base × height
3 complete square and 3 more than half square 2
1
2
2
2
2
2
So, area = (3 × 1) cm + (3 × 1) cm = 3 cm + 3 cm = 6 cm . = 2 × 4 × 3 = 6 cm 2
FINDING AREA BY USING A SQUARED PAPER
A squared paper is a convenient tool for determining the approximate area of a region enclosed by a rectangle, a
triangle, a parallelogram or any simple closed figure. If the figure encloses an exact number of complete squares,
then we simply count and state the area. If the figure cuts across squares of the squared paper, then we follow the
steps given below:
1. We count the number of complete squares enclosed by the figure.

2. We count the number of squares which are more than half enclosed by the figure. We treat each such square
as one complete square and ignore the other squares which are less than half enclosed by the figure.

3. We count the number of squares which are exactly half enclosed by the figure and take two of them as one.
The sum of the number of complete squares obtained in steps 1, 2 and 3 gives approximate number of complete
squares enclosed by the figure.