Question

24. The area of the four walls of a room is 120 m2. The length is twice the breadth. If height of
the room is 4m, find the breadth.

please answer correctly​

Answer 1

Given

• Area of four walls of a room is 120m².
• The length is twice the breadth.
• Height of the room is 4m.

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To find

• Breadth of the room.

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Solution

• Let the breadth of the room be b.

Then,

• Length of the room will be 2b.

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Note:- Area of four walls means the lateral surface area of the room.

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★ Therefore, we will use the formula of lateral surface area of cuboid.

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$\: \: \: \: \: \: \: \: \: \: \: \: \boxed{\tt{\bigstar{LSA_{(Cuboid)} = 2(l + b) \times h{\bigstar}}}}$

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Here

• l = length
• b = breadth
• h = height

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$\tt:\implies\: \: \: \: \: \: \: \: {LSA = 120}$

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$\tt:\implies\: \: \: \: \: \: \: \: {2(l + b) \times h = 120}$

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$\tt:\implies\: \: \: \: \: \: \: \: {2(2b + b) \times 4 = 120}$

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$\tt:\implies\: \: \: \: \: \: \: \: {2(3b) = \dfrac{120}{4}}$

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$\tt:\implies\: \: \: \: \: \: \: \: {6b = 30}$

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$\tt:\implies\: \: \: \: \: \: \: \: {b = \dfrac{30}{6}}$

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$\bf:\implies\: \: \: \: \: \: \: \: {b = 5}$

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Hence,

• The breadth of the wall is 5m.

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