I wanted to thank everyone who's been replying and trying to help. I have been checking measurements on right triangles and the hypotinous is 7/8 bigger, although is seems different than what I'm remembering from high school geometry.
PianoDebbie -- your square in a square link was great. It was a huge help.
Possibly silly question -- when connecting a triangle to a rectangle do you match them on he edge or do you center them? I think I just figured out centering them was important.
So I've sucessfully designed and pieced my first block. It's a little wonky in a couple places, but its improving.