Yup, measuring is the key. If you need a printable reference sheet that shows you how to do it, I have one available here:

http://www.andicraftsquilting.com/learn.htm

Thank you so much to all that replied. Have been working on call and not had time at the computer. This was my first posting and I can't express how tickled I was at you all taking the time to respond. Thank you so much. There's is always something to learn when it comes to quilting! Thank you again and happy holiday's to you all.