Nina wants to put color tiles on a square . 3 color tiles fit acroos the top of the square . how many rows and colum of tiles will nina need. how many square tiles will she use in all

A square has all the sides being equal.
Since the top can fit 3 color tiles, then the side must fit the same number of tiles.
Therefore, 3 roles and 3 columns of tiles will be required.
The number of tiles required will calculated similar to area of a square. That is,

Number of tiles = 3*3 = 9 tiles.