Calculating the Area of Four Walls
The question asks for the total area of the four walls of a room given its dimensions: length (l), breadth (b), and height (h).
Area Formula for Four Walls
The area of the four walls of a rectangular room is calculated using the perimeter of the floor multiplied by the height of the room. The formula is:
Area = $2 \times (\text{length} + \text{breadth}) \times \text{height}$
In mathematical terms:
Area = $2(l + b)h$
Applying Given Dimensions
Given values are:
- Length ($l$) = 15 m
- Breadth ($b$) = 20 m
- Height ($h$) = 30 m
Step-by-Step Calculation
- Sum the length and breadth: $l + b = 15 \text{ m} + 20 \text{ m} = 35 \text{ m}$
- Calculate the perimeter of the floor: Perimeter = $2 \times (l + b) = 2 \times 35 \text{ m} = 70 \text{ m}$
- Calculate the area of the four walls: Area = Perimeter $\times$ height Area = $70 \text{ m} \times 30 \text{ m}$ Area = $2100 \text{ m}^2$
Final Answer
The area of the four walls of the room is $2100 \text{ m}^2$. This corresponds to Option C.
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Important Questions from 3-D Mensuration
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Take $\pi = \frac{22}{7}$ - The volume (in $m^3$) of a cube, each of whose edges is 42 m, is:
The length and breadth of a cuboid are 50 cm and 75 cm, respectively. If the length of the diagonal is $17\sqrt{29}$ cm, then what is the volume (in $cm^{3}$) of the cuboid?
