I'm sure we'll be able to explain you how to use those graphs but the problem is that different aircraft manufacturers use different types of graphs for the W&B. Scan or take a (good) picture of the graph from the POH and post is here.
I'll be able to help you out as soon as I know exactly what your looking at.
I am pretty sure I have the weights and balance figured out. I am using the graph from Jeppsons FAA airmans knowledge test.
(fig. 33, 34, 35) looks just like what Tupac posted.
I followed examples until I understood it. Its hard as hell to get the moments precise when using a chart unless there is a trick I don't know.
Calculate the moment of the airplane and determine which category is applicable.A. 79.2 utility category B. 80.8 utility category C. 81.2 normal category.
pilot and passenger weight 310 follow line to right until it intersects with station line for pilot and front passenger. follow line down to load and moment/1000 pound-inches. ok but it is 11.6 how can you tell that from the chart the line is some where in the middle of 11 and 12. a 11.6 is a guess at best . I guessed 11.5. by the time I added up all my moments and divided by weight to find arm. I got the wrong answer. Because the test question is B which is right in the corner of the utility category envelope.
I thought I was doing something wrong. It just wasn't accurate enough. I finally got it by multiplying the weight times arm = moment.
My thoughts are chart is useful for quick calculation but not precise, but if you have table that list the arm for front seats then a calculator is much faster and precise.
Let me know what you guys think and what you found in the real world.