Question

which grid does not represent a perfect square?

Explanation:

Step1: Count cells in first grid

$2 \times 2 = 4$, which is $2^2$ (perfect square).

Step2: Count cells in second grid

$4 \times 4 = 16$, which is $4^2$ (perfect square).

Step3: Count cells in third grid

$3 \times 4 = 12$, which is not a perfect square (no integer $n$ where $n^2=12$).

Step4: Count cells in fourth grid

$3 \times 3 = 9$, which is $3^2$ (perfect square).

Answer:

The third grid (3 rows, 4 columns, 12 total cells) does not represent a perfect square.