Answer
$8.4*10^{7}km$
Work Step by Step
We are given a length of 10 light years, so $L=10ly$, or in meters, we have $L=9.46*10^{16}m$.
We can use right triangle trigonometry we found in part a ($\theta_R= 8.8*10^{-7}rad$) to find the distance between the stars, d.
$\sin \theta = d/L$
$d=L\sin \theta $
$d=9.46*10^{16}m*\sin 8.8*10^{-7}rad$
$d= 8.4*10^{10}m$
$d= 8.4*10^{7}km$
