$y={\left( \frac{ 3 }{ 2 } \right)}^{2}$
To raise a fraction to a power, raise the numerator and denominator to that power$\begin{align*}&y=\frac{ 9 }{ 4 } \\&\begin{array} { l }\begin{array} { l }y=2 \frac{ 1 }{ 4 },& y=2.25\end{array},& y={\left( \frac{ 3 }{ 2 } \right)}^{2}\end{array}\end{align*}$