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.
Similar Questions
- The radius of a sphere is 16 cm. Find its surface area.
- What is the ratio of volumes of two spheres where the curved surface areas are in the ratio of $1 : 4$?
- Five solid cubes, each of volume $39304 \text{ cm}^3$, are joined end to end to form a cuboid. What is the lateral surface area (in $\text{cm}^2$) of the cuboid?
- What is the surface area of a sphere of radius 8 cm? (use $\pi = 3.14$)
- The ratio of the volumes of two cubes is 64 : 1331. What is the ratio of their total surface areas?
- The diameter of a hemisphere is 7 cm. What will its total surface area be?
- The diameters of the bases of two cones are equal. If their slant heights are in the ratio of 3 : 4, then what will the ratio of their curved surface areas be?
- A cube of volume 324 cm$^3$ is molded into a cuboid whose length, width and height are in the ratio $3 : 2 : 2$. Find the length of the cuboid.
- An aquarium is in the form of a cuboid whose external measures are $80 \text{ cm} \times 30 \text{ cm} \times 40 \text{ cm}$. The base, side faces and back face are to be covered with a coloured paper. Find the area of the paper needed?
- A godown is in the form of a cuboid of measures $60 \text{ m} \times 40 \text{ m} \times 30 \text{ m}$. How many cuboidal boxes can be stored in it if the volume of one box is $0.8 \text{ m}^3$?
Important Questions from 3-D Mensuration
Find the total surface area of a closed cylinder having a base radius of 70 m and a height of 110 m. [Use π = \(22\over7\)]
- The curved surface area of a cylinder is half of its total surface area. If its height is 195 cm, then find its diameter (in cm).
The diameter of the base and slant height of a right circular cone are 30 cm and 113 cm, respectively. Find the volume (in cm³) of the given cone.
(Use $\pi = \frac{22}{7}$)- A cylindrical rod has an curved surface area of $4,900 \text{ cm}^2$. If the length of the rod is 97 cm, then the radius (in cm) of the rod, correct to two places of decimal, is:
Take $\pi = \frac{22}{7}$ - The volume (in $m^3$) of a cube, each of whose edges is 42 m, is:
