How to create horizontal gridlines on a circle or shape?

I have a need to divide circles or shapes up HORIZONTALLY into say 100 pieces, then be able to click on those lines to show the width.  When I split into grid or use the grid tool, it creates a square.  I can then use a circlular clipping mask, and it looks fine, but when I go to get the width measurement of the line it simply gives me the measurement for the original square.  All I have been able to come up with is to then use the line tool to basically copy the line within the circle, then measure that line.  Way too much work.....any ideas? 

Here is what I need my end result to be...measureable lines.  So, when I click on the red line in the pic (and every other line), I get the width.

Any help would be much appreciated.

Thx

Sue

www.suemcnenly.com