Book to help with quilting math?
I have an idea for a quilt made entirely of squares... well, almost entirely. Some of the squares will be comprised of half-square triangles. I need to know what size those triangles need to be so that when I sew them together with a 1/4-inch seam, they'll result in a 2.5-inch square to match all the other squares in the quilt. I know there has to be a relatively easy way to understand this stuff, but it's not intuitive for me at all.
I went to Amazon and searched for quilt math to see if there's a book that can help me understand how to figure out such vexing word problems. LOL (It's been a looooong time since high school math!) I didn't find anything.
Can anyone recommend a book that helps you figure out sizes when you're not following a pattern?