Page 147 - ICSE Math 5

P
10 Perimeter and Areaerimeter and Area

Learning Outcomes

Students will be able to learn:
 to find the perimeter of simple geometrical shapes.
 to find the area of simple geometrical shapes.

Perimeter

Perimeter of a closed figure is the sum of all its sides or the total length of its boundary. Perimeter
of a figure can be calculated by measuring all the sides of the given figure using a ruler or a
measuring tape.

Perimeter of a figure = Sum of all its sides

Example 1: Find the perimeter of the given figure.
A 6 cm B

3 cm 2 cm
C
F
3 cm
4 cm
E 5 cm D
Solution: Perimeter of the given figure = Sum of all its sides

= AB + BC + CD + DE + EF + FA
= 6 cm + 2 cm + 3 cm + 5 cm + 4 cm + 3 cm
= 23 cm

So, the perimeter of the given figure is 23 cm.

Perimeter of a Rectangle

A rectangle is a simple closed figure with 4 sides in which opposite sides are equal.
Let’s find the formula for perimeter of a rectangle using the definition of perimeter.

In the given rectangle PQRS, the two lengths are PQ and RS; and the two breadths are QR and SP.
Length (l)
P Q

Breadth (b) Breadth (b)

S R
Length (l)

137