ANSWER
The coordinates of the image are (2,2)
EXPLANATION
The mapping for a reflection across the line y=k is :
We want to find the image of the point (2,-4) after a reflection in the line y=-1.
In this case k=-1.
This simplifies to,
Hence the image is (2,2)
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
Where, h is height, l is length and b is breadth.
Perimeter of the rectangular base is 2(l+b). So,
Putting the given values, we get
Therefore, the area of 4 walls of the room is 54 sq. metres.