Page 169 - Math Skill - 5

Perimeter, Area and Volume 167

2. The sides of some squares are given below. Find their perimeter using the formula.
(a) Side = 6.4 m (b) Side = 6.8 cm (c) Side = 125 cm

3. Find the missing entry of the rectangle for each of the following:

Perimeter 56 cm 192 cm 120 cm 64 cm 144 cm
Length 18 cm 20 cm 48 cm

Breadth 46 cm 30 cm

4. Find the side of the square for each of the following:

Perimeter 32 cm 48 cm 108 cm 144 cm 324 cm

Side

Area

You know that a figure is always drawn on a plane. You also know that a closed figure encloses
a certain part of the plane. The enclosed part of the plane forms the interior region of the figure
and the rest of the plane forms its exterior. The region enclosed by a figure is called its area.
Observe the following figures carefully and identify the interior region of each figure and

colour it the way you want using crayons.

The region enclosed by each figure which you just have coloured is the area of that figure. Just
like the above figures, each and every surface has a definite area.
Look closely and you will discover many more examples of real surfaces having an area.

The number of square units need to cover the surface of a plane figure is its area.
If = 1 square cm, then area of the below shaded part is 16 square cm.

4

5 3
6 7 2 1
8 9 10 16

11 12 13 15
14

Area of Figures not Covering Whole Squares

There are some shapes which do not cover the whole squares, or complete squares. To find the
area of such figures, we have to consider half-squares besides complete squares.