dreaded math question
 

I am needing to make a 4 patch that will be 3" when sewn into a block/quilt unfinished it needs to be 3 1/2" my question is the strips I cut the 4 patchs out of they need to be cut at 2"s right?(i plan on strip piecing and cutting them that way. I am feeling really stupid right now because I am having trouble with this simple math problem.

Yep - think of it this way:
a finished 3" 4p consists of 4 squares that finish at 1 1/2" (3"/2 squares across = 1 1/2" per square). Assuming you are doing the standard 1/4" seam allowance, you add 1/2" to the "finished size" of the square to get 2" squares and therefore you use 2" strips to make the 4patch.