in excel 2002, how do i define the cell size by inches?

I don't have an older version of Excel to test with, but perhaps something similar to the instructions here...
https://www.automateexcel.com/how-to/change-cell-size-pixels-inches
Essentially you'd change the default "ruler" from pixels to inches, then in Page Layout view, use Format Cells > Column (or Row) to set the width/height in inches.

I cannot find a default "ruler" option in my copy of 2002 as shown in Paul's link. I can find a default "ruler" option in my copy of 2007. Scanning the help files for 2002, I do not find anything that talks about changing the default measurement unit for column width and row height. In these help files, they repeatedly say that the "unit" value used in the column width dialog is "average number of 0-9 digits that fit using the standard font. You might be able to infer something about the width (in inches) by knowing something about the average width of numbers in your standard chosen font.

In the end, though, I expect it will be best to try a couple of different settings and relate the number entered to the actual width you see (whether on screen or in print -- depending on which version is most important to you). After a few direct measurements, it should be possible to develop a column width number to inches conversion that you can store in your head or in a spreadsheet or on sheet of paper near your computer. Repeat for the row height numbers. Then you can use your unit conversion to enter numbers that will correspond to your desire column width and row height.

Upon further research, it appears that the default unit for column width and row height is "points" (whatever that means). This Q&A suggests that the conversion for row height is 72 points per inch and column width is 12 points per inch. So, 5 inches wide should be 5*12=60 column width points and 3 inches high should be 3*72=216 row height points. https://answers.microsoft.com/en-us/...d-e391c0ab635f

See if that helps.