I'm working on my physics prelab, but I can't seem to get this answer. The question states: Measuring the detector´s output as a function of its position along the goniometer (look it up!), we see that there are maxima and minima in the signal. Starting at one of the maxima, we find 6 additional maxima after moving the reflector a distance of 8.91 cm. Therefore, the frequency of the microwaves from this generator is ____________. The answer is supposed to be in GHz. I've tried using the equation nλ=dsinθ where x≈dsinθ and λ=c/f. That would give f = c*n/x where x = 8.91 cm and n = 6. This gave me 20.2 GHz, but apparently isn't the right answer... Help please??