Grade 7 - Mathematics 9.41 Area of the Four Walls of a Room - I
Example:
If the length, width and height of a room are 7 metres, 8 metres and 6 metres respectively. Find the total area of four walls.
Solution:
Given that, length (l) = 7 metres, width (b) = 8 metres and height (h) = 6 metres
The total area A = 2h (l+b)
ie A = 2 * 6 (7+8)
= 12 * 15
= 180 square metres.
Hence the total area of the four walls = 180 square metres.
Example:
If the length of a room is twice its width and the height of the room is given by 3 centimeters then, find the width of the room. Given the total area of four walls is 216 square centimeters.
Solution:
Let 'x' be the width of the room.
Then the length (l) = 2x and given that the height (h) = 3 centimeters.
The area is A = 2h (l+b).
ie 2 * 3 (2x+x) = 216.
ie 6 * 3x = 216.
ie x = 216/18 = 12.
Hence the width of the room = 12 centimeters.
Directions: Read the above example carefully and answer the following questions:
Find the total area of the four walls of a hall, if its height, width and length are x, 2x and 3x respectively. Also find the area when x = 4 centimeters.
(Answer:- 10x)
If the length of a room is three times its width and the height of the room is given by 6 metres then find the width of the room. The total area of four walls is given by 192 square metres.
(Answer:- 4 metres)