match range of axes from one plot to another
 

My spreadsheet has about 4 plots in different sheets and i wanted to combine
these charts into one sheet with new formatting. I matched up the data using:
Sheets("For Paper").ChartObjects("Chart 1").Chart.SeriesCollection(1).Formula
= Sheets("Chart4").SeriesCollection(1).Formula

Now I want to include in my macro a way to match the range of the x and y
axes. On my original plot, one of the plottted series is a 45 degree line
that extends from the minimum of x and y to the maximum of x and y. I was
thinking of possibly referring to the array from xvalues and pulling the
first value and second value to be linemin and linemax, but i'm not sure how
to do it. any ideas?