Answer
No, their ratio can be determined, but not the individual quantities.
Work Step by Step
Consider equation 25–10, which applies to x-ray diffraction.
$$m\lambda=2dsin\phi$$
For each diffraction peak, we measure the angle and by counting, know the order m.
$$(1)\lambda=2dsin\phi_1$$
$$(2)\lambda=2dsin\phi_2$$
$$(3)\lambda=2dsin\phi_3$$
The equations allow us to find the ratio of wavelength to lattice spacing.
$$\frac{\lambda}{d}=2sin\phi_1=sin\phi_2=\frac{2}{3}sin\phi_3$$
We know their ratio but lack sufficient information to individually determine the wavelength $\lambda$, or the lattice spacing d.