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Volume and Surface Area Questions And Answers.
Exercise ::
Volume and Surface Area
1. A right triangle with sides 3 cm, 4 cm and 5 cm is rotated the side of 3 cm to form a cone. The volume of the cone so formed is? A. 12 ∏ cm3 B. 15 ∏ cm3 C. 16 ∏ cm3 D. 20 ∏ cm3
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Published by:Michael Daani
2. In a shower, 5 cm of rain falls. The volume of water that falls on 1.5 hectares of ground is? A. 75 cu. m B. 750 cu. m C. 7500 cu. m D. 75000 cu. m
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Answer: Option B
Explanation:
1 hectare = 10,000 m2
So, Area = (1.5 x 10000) m2 = 15000 m2 .
Depth =
5
m
=
1
m.
100
20
15000 x
1
3 = 750 m3 .
20
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3. A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls, the volume of the hall is? A. 720 B. 900 C. 1200 D. 1800
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Answer: Option C
Explanation:
2(15 + 12) x h = 2(15 x 12)
=> h = 80/27m =20/3m
∴ Volume =15 x 12 x
20
3 = 1200 m3 .
3
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4. 66 cubic centimetres of silver is drawn into a wire 1 mm in diameter. The length of the wire in metres will be? A. 84 B. 90 C. 168 D. 336
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Answer: Option A
Explanation:
Let the length of the wire be h .
Radius= 1/2 mm =1/20cm. Then,
=> 22/7 x 1/20 x 1/20 x h = 66.
=> h = [(66 x 20 x 20 x 7)/22] = 8400 cm = 84 m.
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5. A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3 , then the weight of the pipe is: A. 3.6 kg B. 3.696 kg C. 36 kg D. 36.9 kg
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r2h =
cm3
Volume = (Area x Depth) =
m3