I ended up not having to cut 160 triangles. Instead the book taught me a trick on how to go from 80 squares directly to 80 squares made out of 2 triangles each without having to cut the squares into halves first.
Do you want to know how to do it?
First, you put two squares on top of each other - the right sides together.
Then you draw a line diagonally thru the middle, pin both pieces together and sew on both sides of the line (about 1/4" away from the line on each side - you can barely see the seams in this picture).
Finally you cut along the line and when you open up the pieces you have new squares!
In the end you just iron the seams to one side. I felt like this was an awesome trick that saved me a bunch of time. So now I have 80 squares made out of 160 triangles:)
Whats next? The fun part! Putting all of these together to create one side of the quilt!