Question 1017298:  What is the side length of the largest square tile that can be used to tile a rectangular floor measuring 12 ft by 38 ft if the tiles cannot be cut? 
 Answer by JulietG(1812)      (Show Source): 
You can  put this solution on YOUR website! If the tile cannot be cut and it's a square, then the largest tile is necessarily 12' with a section of 2x12 left untiled.  However, if the full floor must be tiled with none left over, then: 
We know that the tiles must be 1', 2', 3', 4', 6', or 12' (what goes into 12) 
Which of these also go into 38"?  Only 1 and 2.  Therefore the largest square tile is 2'. 
6 - 2' tiles across, 19 rows of 2' down 
 
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