Double Slits, Calculating Wavelength

[STEMucator]

Homework Statement

The following data was obtained upon using a double-slit experiment. Use this data to determine the wavelength of light being used to create the interference pattern. Do this in three different ways.

- The angle to the eight maximum is 1.12°
- The distance from the slits to the screen is 302 cm
- The distance from the first minimum to the fifth minimum is 2.95cm
- The distance between the slits is 0.025cm

Homework Equations

The Attempt at a Solution

My work is shown in this image: http://gyazo.com/b9625064b97100febb726a6f6a12236a

I believe I have interpreted the information correctly. I also believe methods 1 and 3 are correct as they were the most obvious. I have placed a series of question marks on method 2, which I am having trouble understanding. I don't believe they have given me sufficient information to solve this problem as is.

After I have 3 values for wavelength, I plan to average them out to get a final answer.

Does anyone have any insight to this? I seem to be missing a very important variable and I'm not sure how to go about it.

 

[STEMucator]

Friendly bump, Is it safe to say this problem is not solvable?

If I knew the distance from a nodal line to the right bisector I could solve this, but I can't see how to get it for some reason.

All I seem to know is the distance between two consecutive nodal points, namely $\Delta x = 0.7375cm$.

Would that mean half of that distance, $\frac{\Delta x}{2}$, is the distance between a node and an antinode?

If so, could I not consider the distance between the central maximum (which is exactly where the right bisector would happen to be) and the closest node to it? That would give me a workable value of $x_1 = \frac{\Delta x}{2}$ and $n = 1$.

This doesn't feel right to me though, does anyone have any thoughts?