To solve the equation \( 16 = x^2 \), we can take the square root of both sides.
Taking the square root gives us:
\[ x = \pm \sqrt{16} \]
Since \(\sqrt{16} = 4\), we have:
\[ x = \pm 4 \]
Thus, the solutions are:
\[ x = 4 \quad \text{or} \quad x = -4 \]