From the XRD of aluminum powder Hull determined the lattice to be fec, with lattice cell size \(a=0.405 \mathrm{~nm}\) (modern value). He observed strong interference at Bragg angle \(\theta=17.25^{\circ}\) using a molybdenum X-ray tube ( \(\lambda=0.0714 \mathrm{~nm}\) ). He assigned Miller index 311. Show that this measurement is consistent with \(a\).