Using a refracting telescope, you observe the moon when it is $3\mathrm{.}84{10}^{8}m$ from Earth. The diameter of the objective lens of the telescope is $0\mathrm{.}750$ m $.$ Use $550$ nm for the wavelength of light.

$r=0\mathrm{.}375,=550{10}^{-9}$

What is the minimum feature size $x$ on the surface of the moon, measured in kilometers, that your telescope can resolve?