Here is a great link to find out what you need to score on the final to receive an A, B, C, etc. Just leave out the 20 in the percent column, which is what the final is worth. Then, in step 2 put in 85 for an A, 75 for a B, and 65 for a C. Hope this helps if interested in knowing what you need to score on the final for a particular grade.
http://www.conquercollege.com/gradecalc/semester exams: 55%
clicker: 10%
homework: 15%
final: 20%