If something has a spearman rank of 1 what would the angle of the line of best fit be?

Question

would it be 90 degrees or 45 or something else?

Answer 1

A Spearman rank of 1 means that the datum in question is the smallest in the data set. This says nothing about the line of best fit. Are you trying to ask about a Spearman rank correlation coefficient of 1? In this case, you still don't know the line of best fit for the original data -- any such conclusions you draw will be about the rank data, not about the actual best fit line.

In general, a correlation coefficient of 1 means that the two data sets form a straight line with positive slope. In the case of Spearman ranks, it means that the data *ranks* are in perfect step: lowest X value matches the lowest Y value, and so on. This gives you the data set (1,1), (2,2), (3,3), ...
The slope of this line is left as an exercise for the reader.