1. The problem statement, all variables and given/known data Calculate the grating constant, d, given that theta = 172.01167 degrees, and that lambda = 447.2 nanometers. 2. Relevant equations d = mλ / sinθ where m is an integer that refers to the order of diffraction where λ is the wavelength where d is the spacing between two slits where θ is the angle observed 3. The attempt at a solution I understand the equation, but given the fact I have two variables (being m and d) I am unsure of how to solve. How do I determine the order of diffraction?