1. The problem statement, all variables and given/known data X-rays 1.54 angstrom reflected off copper powder @ 21.65º 25.21º 37.06º 44.96º 47.58º 2. Relevant equations nλ = 2d sin(Θ) ; the Bragg equation 3. The attempt at a solution The cubic latice is face centered at d110? 5 planes? I tried plotting sin(Θ) vs. n to get the slope and calculate a, but it doesn't seem right? How do I find the length of an edge of the unit cell and what is the cubic lattice?