Answer
$1.71\times 10^7m$
Work Step by Step
We know that
$r=(\frac{GMT^2}{4\pi ^2})^{\frac{1}{3}}$
We plug in the known values to obtain:
$r=(\frac{(6.67\times 10^{-11})(0.108\times 5.97\times 10^{24})(8.86424\times 10^4)}{4\pi^2})^{\frac{1}{3}}=2.05\times 10^7m$
Now we can find the required altitude as
$h=r-R$
We plug in the known values to obtain:
$h=2.05\times 10^7-0.3394\times 10^7$
$h=1.71\times 10^7m$