Page 156 - Maths Class 05

10 Perimeter and Area

Perimeter means distance around a figure or curve. We can only measure perimeter of a
closed figure / 2-dimensional shape or curve as movement around a closed figure or curve
is possible.

The common units are kilometer (km), meter (m), centimeter (cm) etc. Suppose, there is
a square plot and each side of the lot is 1 km in length. Hence, the perimeter of the plot

will be 4 km.
Perimeter of a Rectangle

Perimeter is the length of the boundary of any figure or shape.

In the rectangle shown, the perimeter will be the sum of all its sides.

Perimeter = l + b + l + b l

= l + l + b + b b b
= 2 (l + b)
l
Perimeter of a rectangle = 2 (length + breadth)
Example : Find the perimeter of a rectangle whose length is 8 cm and breadth is

4 cm .

Solution : Length of the rectangle = 4 cm
Breadth of the rectangle = 3 cm

Perimeter = 2 (length + breadth)

= 2 (4 + 3)
= 2 × 7
3 cm
= 14

Hence, the perimeter of the rectangle is 14 cm . 4 cm
Example : The perimeter of a rectangle is 83 cm . If the length of the rectangle is
3 cm , find the breadth.

Solution : Perimeter of the rectangle = 83 cm

Length of the rectangle = 3 cm

Perimeter = 2 (length + breadth)
83 = 2 × length + 2 × breadth

Mathematics-5 156