Page 228 - ICSE Math 6

Example 14: Convert the following as indicated.
(a) 2 hours to minutes (b) 3 m to cm (c) 350 g to kg

(d) 1,700 mL to L (e) ` 7.50 (f) 360 mm to km
Solution: (a)  1 hour = 60 minutes \ 2 hours = 2 × 60 = 120 minutes
(b)  1 m = 100 cm \ 3 m = 3 × 100 = 300 cm
1
(c) 1 kg = 1,000 g \ 1 g = 1000 kg
350
So, 350 g = = 0.35 kg
1000
1
(d)  1 L = 1,000 mL \ 1 mL = 1000 L
1700
So, 1,700 mL = = 1.7 L
1000
(e)  ` 1 = 100 paise \ ` 7.50 = 7.50 × 100 = 750 paise

360 1
(f) 360 mm = = 36 cm (1 mm = cm)
10 10
360 1
36 cm = = 0.36 m (1 cm = m)
100 100
0.36 1
0.36 m = = 0.00036 km (1 m = km)
1,000 1000
Example 15: Find the area of the rectangles whose sides are:
(a) 6 cm and 4 cm (b) 1 km and 500 m (c) 3 m and 80 cm
Solution: Area of a rectangle = Length × Breadth
(a) Area of rectangle = 6 cm × 4 cm = 24 sq. cm
(b) Area of rectangle = 1 km × 0.5 km = 0.5 sq. km ( 500 m = 0.5 km)
(c) Area of rectangle = 3 m × 0.8 m = 2.4 sq. m ( 80 cm = 0.8 m)

Example 16: Find the area of the squares whose sides are:
(a) 6 mm (b) 12 cm (c) 15 m
Solution: Area of a square = Side × Side
(a) Area of a square of side 6 mm = 6 mm × 6 mm = 36 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

2
Example 17: Find the perimeter of a square whose area is 169 m .
Solution: Area of a square = side × side

2
 169 m = 13 m × 13 m = side × side \ side = 13 m
Also, perimeter of square = 4 × (length of a side)
= 4 × 13 m = 52 m

2
Example 18: The area of a rectangular plot is 145 m and its length is 5 m. Find the length of a wire
required to fence the plot.
Area
Solution: Breadth of rectangle =
Length of rectangle
145 m 2
= = 29 m
5 m

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