Incorrect. Factor the numerators and denominators.

$\displaystyle\frac{{{9}{a}}}{{4}}\cdot\frac{{8}}{{{15}{{a}}^{{2}}}}=\frac{{{3}\cdot{3}\cdot{a}}}{{{2}\cdot{2}}}\cdot\frac{{{2}\cdot{2}\cdot{2}}}{{{3}\cdot{5}\cdot{a}\cdot{a}}}\usepackage{cmbright}\Huge\$

Regroup so that the common factors on top and bottom are in one fraction. This can be reduced to 1. Multiply the simplified expressions.