Answer
$\frac{5}{7}$
Work Step by Step
$\sqrt {\frac{25}{49}}$
According to the textbook, a number, $a$, is a square root of another number, $b$, if $a^2=b$. Since $(\frac{5}{7})^2=\frac{25}{49}$, $\frac{5}{7}$ is a square root of $\frac{25}{49}$.