1. The problem statement, all variables and given/known data See attached image 2. Relevant equations y=L*tan(theta) m*(lambda)=d*sin(theta) 3. The attempt at a solution Lambda = 640 nm = 6.4x10^-4 mm m*(lambda)=d*sin(theta) 1*(6.4x10^-4 mm) = (0.25 mm)*sin(theta) theta = 0.15 degrees y = L*tan(theta) This is where I am not sure. I know I need to plug in y and theta. But I think my y value is wrong. How can I know for sure what the distance between the maxima are? The graph that is given seems to be too poor to tell.