Answer
Please see the work below.
Work Step by Step
We know that
$F=K\Delta x$
This can be rearranged as
$K=\frac{F}{\Delta x}$
We plug in the known values to obtain:
$K=\frac{0.373\times 10^{-12}}{2.30\times 10^{-6}}=1.62\times 10^{-7}\frac{N}{m}$
