1. The problem is to evaluate $(-5)^2$. 2. The formula for squaring a number is $a^2 = a \times a$. 3. Here, $a = -5$, so we calculate $(-5)^2 = (-5) \times (-5)$. 4. Multiplying two negative numbers results in a positive number, so $(-5) \times (-5) = 25$. 5. Therefore, the final answer is $25$.