Answer :
Note: The height of the room must be 3 m instead of 3 cm because 3 cm is too small and it cannot be the height of a room.
Given:
Perimeter of the floor of a room = 18 metre
Height of the room = 3 metre
To find:
The area of 4 walls of the room.
Solution:
We know that, the area of 4 walls of the room is the curved surface area of the cuboid room.
The curved surface area of the cuboid is
[tex]C.S.A.=2h(l+b)[/tex]
Where, h is height, l is length and b is breadth.
Perimeter of the rectangular base is 2(l+b). So,
[tex]C.S.A.=\text{Perimeter of the base} \times h[/tex]
Putting the given values, we get
[tex]C.S.A.=18\times 3[/tex]
[tex]C.S.A.=54[/tex]
Therefore, the area of 4 walls of the room is 54 sq. metres.