Question 738199
12 feet + 10 inch = 154 inches
10 feet + 1 inch = 121 inches


Representing the room with a rectangle, 154 units from left to right, and 121 units from up to down, we can split this rectangle into a square 121 by 121 and a smaller rectangle 33 by 121.  


To fit the 121 by 121 square with square tiles, the size can well be 11 inch square tile.  You could fit 11 of these tiles on width and 11 of these tiles on length.  Note that {{{11^2=121}}}.


The same size tile of 11 by 11 inch*inch would continue in the 33 inch by 121 inch rectangular region adjacent to the 121 by 121.  


ANSWER: Size of square tile, 11 inch by 11 inch.