1.A cube has an edge measuring 8cm. Find the number of cubes of edges 2cm that can be cut of from it.

2.The area of the floor of a room is 67.5 sq m. Its volume is 270 m3 . Find the height of the room.

3.How many cubic blocks of wood of side 20 cm can be cut from a block of wood having dimensions of 2 m x 80 cm x 40 cm.

4. If the length of each edge of a cube is doubled how many times does its volume became? How many times does its surface area became?

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Answers

2016-01-17T10:17:30+05:30
Answer for first question is
The volume of big cube=8*8*8=512
Volume of small cube=2*2*2=8
Volume of big cube/volume of small cube =number of small cubes so.
512/8=64
So 64 cubes made from big cube
Answer for 3rd question..
1m=100cm
2m=200cm
Volume of cubiod=200*80*40= 640000cm3
Volume of cube= 20*20*20=8000cm3
Divide volume if cubiod/volume of cube=num of cubes

640000/8000=80 cubes

So 80 cubes are made from cubiod

Answer for fourth question
Let edge of cube = a
Volume of cube=a3
If side is doubled then side=2a
Volume with new side=8a3
So the volume became 8 times
Surface area =6*a2
New surface area =6*2a2
So surface area became 4 times


Thanks if i helped uuu
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Jaspreet where is 2nd and and 4th and is wrong..
2nd and is not there and 4th and is wrong
The Brainliest Answer!
2016-01-17T10:33:31+05:30
1. Volume of the first cube = 8×8×8 =512 cm3 Volume of the small cube =2×2×2 =8cm cm3 No. Small cubes that can be placed in the first cube=512/8=64 cubes 2.volume of the room = l×b×h Area of floor = l×b Therefore height= volume/(l×b) =270/67.5 =4m 3.volume of the whole block =200×80×40= 640000 cm3 Volume of a small block that had to be cut. 20×20×20 = 8000 cm3 Volume of the small cube =2×2×2 =8cm cm3 No. Small blocks that has to be cut from the whole block = 640000/8000=80 bolcks 4. Let the length of the edge of the cube be x. So its surface area = 6×x×x Now the edge of the cube is doubled So new edge of the cube is 2x So new surface area of the cube = 6×2x×2x So the no. of times the surface area became of the new cube as compared to the cube of edge x = 6×2x×2x/6×x×x =4 times So the no. of times the became of the new cube as compared to the cube of edge x = 2x×2x×2x/x×x×x = 8 times
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