#### Answer

$\dfrac{27}{32}$

#### Work Step by Step

Use the rule $\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}$ to obtain:
$=\frac{7}{9} \times \frac{3}{8} \times \frac{81}{28}$
Cancel common factors to obtain:
$\require{cancel}
=\frac{\cancel{7}}{\cancel{9}} \times \frac{3}{8} \times \frac{\cancel{81}9}{\cancel{28}4}
\\=\frac{3}{8} \times \frac{9}{4}
\\=\frac{27}{32}
$