For this case we have that by definition, the area of a rectangle is given by:

Where:
w: It is the width
l: It is the length
Thus, the area of the rug is:

We know that the room has an area of
. Subtracting we have:

Thus, the space between the wall and the rug is given by

ANswer:
The space between the wall and the rug is given by
