Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 11

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IMPORTANT

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A swimming pool is $20 m$ long $15 m$ wide and $3 m$ deep. Find the cost of repairing the floor and wall at the rate of $₹ 25$ per square metre.

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Important Questions on Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)

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IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 12

The perimeter of a floor of a room is

30 m

and its height is

3 m

. And the area of four walls of the room is

k m^{2}

, find the value of

k

.

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IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 13

Show that the product of the areas of the floor and two adjacent walls of a cuboid is the square of its volume.

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Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 14

The walls and ceiling of a room are to be plastered. The length, breadth and height of the room are

4.5 m, 3 m

and

350 c m

, respectively. Find the cost of plastering at the rate of

₹ 8

per square meter.

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IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 15

A cuboid has total surface area of

50 m^{2}

and lateral surface area is

30 m^{2}

. If the area of its base is

k m^{2}

what is the value of

k

.

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IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 16

A classroom is

7 m

long.

6 m

broad and

3.5 m

high. Doors and windows occupy an area of

17 m^{2}

. What is the cost of white-washing the walls at the rate of

₹ 1.50

per

m^{2}

.

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8th CBSE

IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 17

The central hall of a school is

80 m

long and

8 m

high. It has

10

doors each of size

3 m \times 1.5 m

and

10

windows each of size

1.5 m \times 1 m

. If the cost of white-washing the walls of the hall at the rate of

₹ 1.20

per

m^{2}

is

₹ 2385.60

, find the breadth of the hall.

EASY

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IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 1

If the length of the longest rod that can be placed in a room

12 m

long,

9 m

broad and

8 m

high is

k m

, find the value of

k

.

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8th CBSE

IMPORTANT

Mathematics for Class 8>Chapter 21 - Mensuration-II (Volumes and Surface Areas of a Cuboid and a Cube)>EXERCISE>Q 2

If $V$ is the volume of a cuboid of dimensions $a, b, c$ and $S$ is its surface area, then prove that

$\frac{1}{V} = \frac{2}{S} (\frac{1}{a} + \frac{1}{b} + \frac{1}{c})$