Page 340 - Math Smart - 7

© Find the perimeters of the rectangle and the square,
a) b)
10m

4 m 15 cm

O Find the perimeters of the rectangle and the square.

a) .. b)
24 cm

14.5 m
15 cm

15.2.2 Area

You have learnt that the area of a figure is the number of square units contained
within the figure. Let us learn to use formulas to find the areas of some
quadrilaterals.

Example 2

Find the areas of the rectangle and the square.
The length and breadth
must be in the same unit a) 14^ b)
before we can calculate
the area or perimeter. 10cm

Solution
a) Area of the rectangle = 14x8 Area = Length x Breadth

= 112m^
b) Area of the square = 10 x 10 Area = Length x Length
=100cm^
The area is 2-dimensional
Area of a rectangle = length of one side x length of the other side
since it is the product of
2 sides — the length and = l X b
breadth.

We use units such as
mm^ cm^ and m^. The breadth {b) length (/)
superscript 2 indicates the
2 dimensions. length (/)

breadth {h)
^3^ UiXJIT 15 I Measuring Time, Area, Perimeter and Volume