Page 178 - Start Up Mathematics_5

Solution: Area of the playground = 400 m 2

Length of the playground (l) = 25 m

Breadth of the playground (b) = Area = 400 m 2 = 16 m
Length 25 m

To find out how much wire will be required to fence it, we need to find the
perimeter of the playground.
Perimeter = 2 × (l + b)

= 2 × (25 + 16) cm
= 2 × 41 cm = 82 cm

So, 82 cm of wire is required to fence the playground.
Example 15: Honey wishes to tile the floor of her drawing room which is 400 cm long

and 250 cm wide. If the area of each tile is 200 cm , how many tiles will
2
Honey require? If each tile costs ` 32, how much will Honey have to
pay?

Solution: Area of one tile = 200 cm 2 5 0 0
2 1 0 0 0
Length of the floor (l) = 400 cm – 1 0
Breadth of the floor (b) = 250 cm 0 0

Area of the floor = l × b – 0
0 0
= 400 cm × 250 cm – 0

= 1,00,000 cm 2 0

Area of floor 100000
Number of tiles required = = = 500
Area of 1 tile 200 Working
So, 500 tiles are required to tile the floor. 5 0 0
Cost of 1 tile = ` 32 × 3 2
1 0 0 0
Cost of 500 tiles = ` 32 × 500 = ` 16,000 + 1 5 0 0 0
So, Honey will have to pay ` 16,000 to tile the floor. 1 6 0 0 0

EXERCISE 13.3

1. The area of a poster is 15 m . If the poster is 5 m long, how wide is it?
2
2. The perimeter of a volleyball court is 60 m. It is 19 m long. Find its width.

3. The perimeter of a square painting is 8 m. How long is its each side?

4. The area of a rectangle is 30 cm . What is the total area of 4 such rectangles?
2
5. The perimeter of a square cardboard is 24 cm. What is its area?

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