graph problem

[northernstar197]

afternoon

i have the following problem (we do this long hand on graph paper)

we take some readings and then plot a graph then slect the two highest points and draw a line through them (with all of the remaining points under the line) then we record the intersection point on the y axis and then calculate the gradient

i have attached a sketch which should help

i would like to automate this into a excel spreadsheet, i can basically do the simple graph but cant plot the line, intersection point or the gradient

any help would be appreciated

thanks

[northernstar197]

is this something that can be done in excel

or is this problem to complicated?

[Andy Pope]

I would say the hard part is determining the top 2 points. if it was the 2 largest then not a problem.

It's hard to tell from seeing 1 set of data what the rules of your data layout are.
Is the data point with the largest X value also the 1 with the largest Y ?

It would also help if you posted example workbook of your current data and chart.

[shg]

A given graph could have several solutions. In the attachment, the following pairs all satisfy the criteria:

1 and 2
2 and 4
4 and 7
7 and 10

How do you choose?

Maybe some background would help?