Page 151 - Maths Class 06

(b) Area of rectangle = 1000 m × 500 m = 500000 m 2
(c) Area of rectangle = 3 m × 0.8 m = 2.4 sq. m
EX AM PLE 2. Find the area of the squares whose sides are:
(a) 8 mm (b) 12 cm (c) 15 m

SOLUTION : Area of a square = Side × Side
(a) Area of a square of side 8 mm = 8 mm × 8 mm = 64 sq. mm
(b) Area of a square of side 12 cm = 12 cm × 12 cm = 144 sq. cm

(c) Area of a square of side 15 m = 15 m × 15 m = 225 sq. m
EX AM PLE 3. The floor of a Varandah is 4 m long and 2 m 50 cm wide. It is to be cov ered com pletely by
the square tiles of side 20 cm. Find the cost of the tiles at ` 5 per tile.
SOLUTION : Length of the Varandah = 4 m = 400 cm

Breadth of the Varandah = 2 m 50 cm = 250 cm
Area of the Varandah = ´l b

= 400 250 sq. cm
´
= 100000 sq. cm
Area of square tile = 20 cm ´ 20 cm

= 400 sq. cm
Area of the Varandah
Number of tile required =
Area of a square tile
100000
= = 250
20 ´20

Total cost of tiles = ` 5 ´ 250 = ` 1250
EX AM PLE 4. Find the cost of car pet ing a room 12 m long and 9 m wide at the rate of ` 85 per sq. m.

SOLUTION : Length of room ( )l = 12 m
Width of room ( )b = 9 m

Area of room = l ´ b = 12 × 9
= 108 sq. m
Cost of carpeting 1 sq. m = ` 85

Cost of carpeting 108 sq. m= 108 × 85
= ` 9180
EX AM PLE 5. Total cost of paint ing a wall at `10 per sq. m is `1000. Find the breadth of the wall, if it
length is 20 m.

SOLUTION : Total cost of paint ing the wall is ` 1000.
Rate of painting = ` 10 per sq. m
\ Total cost = Area × Rate per sq. m

` 1000 = Area × ` 10 per sq. m
Þ Area = 100 sq. m

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