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If V is the volume of a cuboid of dim...

If `V` is the volume of a cuboid of dimensions `a ,\ b ,\ c\ a n d\ S` is its surface area, then prove that `1/V=2/S(1/a+1/b+1/c)`

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We have, V = abc and S = `2(ab + bc + ca)`
`:. (2)/(S) ((1)/(a) + (1)/(b) + (1)/(c)) = (2)/(S) xx ((bc + ca + ab))/(abc) = (2)/(S) xx (S)/(2V) = (1)/(V)`
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RS AGGARWAL-VOLUME AND SURFACE AREA OF SOLIDS-Exercise 15A
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  2. A wall 15 m long, 30 cm wide and 4m high is made of bricks, each measu...

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  3. How many cubic centimetres of iron are there in an open box whose e...

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  4. A box made of sheet metal costs 6480at 120per square metre.If the box...

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  5. The volume of a cuboid is 1536 m^(3). Its length is 16m, and its bread...

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  6. How many person can be accommodated in a dining hall of dimensions (20...

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  7. A classroom is 10 m long, 6.4 m wide and 5m high. If each student be g...

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  8. The surface area of a cuboid is 758 cm^(2). Its length and breadth are...

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  9. In a shower, 5 cm of rain falls. Find the volume of water that falls o...

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  10. Find the volume, the lateral surface area, the total surface area and ...

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  11. The total surface area of a cube is 1176 cm^(2). Find its volume

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  12. The lateral surface area of a cube is 900 cm^(2). Find its volume

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  13. The volume of a cube is 512 cm^(3). Its total surface area is

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  14. Three cubes of metal with edges 3cm, 4 cm and 5 cm respectively are me...

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  15. The length of the longest rod that can be placed in a room of dimensio...

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  16. The sum of length, breadth and depth of a cuboid is 19\ c m and length...

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  17. Each edge of a cube is increased by 50%. Find the percentage increa...

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  18. If V is the volume of a cuboid of dimensions a ,\ b ,\ c\ a n d\ S ...

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  19. Water in a canal, 30\ d m\ w i d e\ a n d\ 12 d m\ d e e p ,\ is f...

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  20. A solid metallic cuboid of dimensions 9m xx 8m xx2 is melted and recas...

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