The area of a square is given by the product of two sides(since they're equal, the square of a side). Since we have to arrange 100 buttons in a square, each column and row are going to have the same amount of buttons, and this amount is given by the square root of 100.
[tex]\sqrt[]{100}=10[/tex]Since the square root of 100 is 10, each row of this square have 10 buttons, therefore, the affirmative saying it has 9 is false.
