Answer
$PE=1.8\times 10^3J$
Work Step by Step
We can find the energy stored as:
$PE=\frac{1}{2}\frac{Q^2d}{\epsilon_{\circ}A}$
We plug in the known values to obtain:
$PE=\frac{1}{2}\frac{(370\times 10^{-6})^2\times 1.5\times10^{-3}}{8.85\times 10^{-12}(8.0\times 10^{-2})^2}=1.8\times 10^3J$
