Question

Pratice set 46
4. A rectangular hall is 12 m long and 6 m broad. Its fiooring is to be made of square
tiles of side 30 cm. How many tiles will fit in the entire hall? How many would be
required if tiles of side 15 cm were used?
5. Find the perimeter and area of a garden with measures
as shown in the figure alongside.
​

Answer 1

Question - 4 :

Given :

• A rectangular hall is 12 m long and 6 m broad.

• Its flooring is to be made of square  tiles of side 30 cm.

To find :

• the number of tiles fit in the entire hall
• the number of tiles required if flooring is to be made of square tiles of side 15 cm

Solution :

⇒ Area of the rectangular hall = number of tiles × Area of each square tile

So, we have to find the area of rectangular hall and area of each square tile.

 Length of the rectangular hall, L = 12 m

 Breadth of the rectangular hall, B = 6 m

Area of the rectangular hall = L × B

    = 12 m × 6 m

    = 72 m²

    = 720000 cm²   [ 1 m = 100 cm ]

(i) If flooring is made of square tiles of side 30 cm

  Area of one square tile = 30 cm × 30 cm

            = 900 cm²

Let the number of tiles be "a"

Area of the rectangular hall = number of tiles × Area of each square tile

720000 cm² = a × 900 cm²

    a = 720000/900

    a = 7200/9

    a = 800

The number of tiles required = 800

(ii) If flooring is made of square tiles of side 15 cm

  Area of one square tile = 15 cm × 15 cm

            = 225 cm²

Let the number of tiles be "b"

Area of the rectangular hall = number of tiles × Area of each square tile

720000 cm² = a × 225 cm²

    b = 720000/225

    b = 3200

The number of tiles required = 3200

Question - 5 :

  Length of each side = 13 m

Perimeter of the given garden is equal to sum of the lengths of all sides.

 Number of sides = 12

Since length of each side is equal ;

⇒ Perimeter of the garden = number of sides × length of each side

Perimeter of the garden = 12 × 13 m

Perimeter of the garden = 156 m

To find the area of the garden, divide it as follows :

        $\setlength{\unitlength}{1cm}\begin{picture}(0,0)\thicklines\put(0,0){\line(0,1){1}}\put(0,1){\line(1,0){1}}\put(1,1){\line(0,1){1}}\put(1,2){\line(1,0){1}}\put(2,2){\line(0,-1){1}}\put(2,1){\line(1,0){1}}\put(3,1){\line(0,-1){1}}\put(3,0){\line(-1,0){1}}\put(2,0){\line(0,-1){1}}\put(2,-1){\line(-1,0){1}}\put(1,-1){\line(0,1){1}}\put(1,0){\line(-1,0){1}}\put(1,0){\line(1,0){1}}\put(1,1){\line(1,0){1}}\put(1,0){\line(0,1){1}}\put(2,0){\line(0,1){1}}\end{picture}$

we'll get 5 squares whose each side is 13 m

Area of each square = 13 m × 13 m = 169 m²

Area of 5 squares = 5(169 m²) = 845 m²

Therefore, area of the garden = 845 m²

Answer 2

Answer:

length of a rectangular hall = 12m

=12×100cm

= 1200cm

breadth of a rectangular hall = 6m

=6×100cm

=600cm

side of a square tile =30cm

no.of tiles = Area of a rectangular hall/area of a

square tile

= lxb/(side)²

=1200× 600/(30)²

=1200× 600/30×30 ( cut 1200and write their up 400 then cut 600and write their 2. cut the down number 3030 and write their 1 and 1

=400×2

= 800tiles

hope it helps you