When finding factors of a radicand (the number under the radical), one of the factors should be a perfect square if the goal is to simplify the radical. For example, if you have \(\sqrt{72}\), you can factor 72 into \(36 \times 2\). Here, 36 is a perfect square, which allows you to simplify the radical:
\[ \sqrt{72} = \sqrt{36 \times 2} = \sqrt{36} \cdot \sqrt{2} = 6\sqrt{2}. \]
In general, finding a perfect square factor can help in reducing the expression in the simplest form. Other factors may also exist, but identifying a perfect square can be particularly useful for simplification.