14682 Views 2 Replies Latest reply: Mar 11, 2011 6:21 PM by Barry
Why not just search "trend" or "trendline" in the Numbers '09 User Guide?
That would take you to page 149 of the guide and the article "Showing Trendlines in Charts," which lists a set of instructions very similar to those in your post.
The Numbers '09 User Guide and the iWork Formulas and Functions User Guide are searchable pdf files, and may both be downloaded through kinks in the Help menu in Numbers. Both are excellent resources to have on hand.
PS: Searching "best fit" will return zero results, but "best" or "best-fit" will get you to the same article.