Page 223 - ICSE Math 6

Example 2: Find the perimeter of a rectangle whose length is 6 m and breadth is 4 m.
Solution: Perimeter of a rectangle = 2 × (l + b)

\ P = 2 × (6 m + 4 m) = 2 × 10 m = 20 m
Example 3: The perimeter of a rectangle is 184 m. If the length of the rectangle is thrice its breadth,
find the length and breadth of the rectangle.
Solution: Let the breadth of the rectangle be ‘x’ m. So, the length of the rectangle is ‘3x’ m.
Perimeter of rectangle = 184 m

\ 184 = 2 × (3x + x)
⇒ 184 = 2 × 4x
184
⇒ x = = 23
8
Thus, the breadth of the rectangle is 23 m and the length is 3 × 23 m = 69 m.
Example 4: The lid of a rectangular box of sides 30 cm by 10 cm is to be sealed all round with tape.
What is the required length of the tape?
Solution: Length of the lid = 30 cm
Breadth of the lid = 10 cm
Required length of the tape = Perimeter of the lid

= 2(Length + Breadth)
= 2(30 + 10) cm = 80 cm
Example 5: A rectangular piece of land measures 0.8 km by 0.3 km. Its each side is to be fenced
with 3 rows of wires. How much wire is required for this job?
Solution: Length of the piece of land = 0.8 km

Breadth of the piece of land = 0.3 km
Perimeter of the piece of land = 2(Length + Breadth)
= 2(0.8 + 0.3) km = 2.2 km
Since each side is to be fenced thrice, therefore the required length of the wire
= 3(2.2 km) = 6.6 km

Example 6: Find the cost of fencing a rectangular park of length 150 m and breadth 100 m at the
rate of ` 10 per metre.

Solution: Length of fencing = Perimeter of rectangular park
= 2(Length + Breadth)

= 2(150 + 100) m = 2(250) m = 500 m

Rate of fencing = ` 10 per metre
∴ Cost of fencing = ` 500 × 10 = ` 5,000
S R
Perimeter of a square

A square is a four-sided closed figure with equal sides and each angle of
90°. Let’s find the perimeter of the square PQRS shown alongside.

P Q
a

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