Answer
$8.8*10^{-7}rad$
Work Step by Step
We assume a wavelength of $550*10^{-3}m$. We are given that we have a telescope with a lens diameter of 76cm, so we can use equation (36-14) to find the angular separation, $\theta_R$, of the two stars.
$\theta_R= \frac{1.22\lambda}{d}$
$\theta_R= \frac{1.22*550*10^{-9}m}{0.76m}$
$\theta_R= 8.8*10^{-7}rad$
