Answer:

Step-by-step explanation:
(2 decimal places)
If you want to arrange the tiles into a square, you will need 3.46 in each row/column.
This is physically impossible, hence you round it down to 3.
(If you round it up, you won't have enough tiles since
)
Thus, the square area will be 
Tiles left: 
Answer:
0
Step-by-step explanation:
-0.1(40)^2+4(40)
-160+160
0