Question

A rational number whose square is $\frac{81}{64}$ is ______ .

Answer 1

Let the rational number be $\frac{p}{q}$ whose square is $\frac{81}{64}.$

$\Rightarrow (\frac{p}{q}{)}^2=\frac{81}{64}$

$\Rightarrow \frac{p}{q}=\sqrt{\frac{81}{64}}$

$=\frac{9}{8}$

Hence, $\frac{9}{8}$ is the required rational number.