These measurements were listed previously but I find they seem to be small. My samples have needed the beginning block 1/4 to 1/2 larger. Best to make a sample and if half square triangle block is too big trim it down.
Starting Block
2" 1"
2 1/2" 1 1/2"
3 1/2" 2"
4" 2 1/2"
5" 3 1/2"
6" 4" I use 6 1/4 for 4" block
7" 4 1/2"
8" 5"
8 1/2" 5 1/2"
9" 6"
10" 7"