I tried LINEST and all others, the main problem is that my data is in 52 columns, 26 for the "Y" and 26 for the "X" values and since the circles are of different radii the columns are of different lengths and excel doesn't like that, I could create a single column of "X" and one of "Y" with all...
I have 26 Mohr circles and need to find c and phi(cohesion and angle of friction)the only way I know to do this if by obtaining the line of best fit for data then getting angle of that line, but I don't know if it is possible to input all the data into the add trend line option for the chart...
