The product of a multiplication problem is \( \sqrt{225} \). First, we can simplify \( \sqrt{225} \):
\[ \sqrt{225} = 15 \]
Since 15 is a rational number, it follows that if the product of two factors is rational, it is possible for both factors to be rational or for one to be rational and the other to be irrational. However, since the product is rational (15), it can be concluded that both factors must be rational.
Thus, the correct response is:
They are both rational because the product is rational.