Originally Posted by
Cedar
So here's where I really started questioning the 7/8 rule. I have. A small 1" square that I want to put in a square as a center motif. That means the the outside triangles have a 1" hypotinous and 3/4 inch square size finished. Would I really use a 1 5/8 sqare to make the outside triangles? Or is there a point where the rule breaks down? It's important to me to learn how to design my own blocks.
OK, now you are dealing with a totally different calculation. There are many different types of triangles. You add 7/8" to the finished size of your target finished patch for Half Square Triangles (HST) only.
I'm not 100% sure what you are asking, but I think you want to put 4 triangles around a center square. This is called a square in square (SIS).
One thing to determine is the finished size of the inside square. Are you cutting a 1.5" square to wind up with a 1" finished size, or are you actually starting out with a 1 inch cut square, in which case the finished size is 0.5"
Here's some good info:
http://www.equilters.com/library/PFP...in-square.html
Here's a calculator:
http://www.quiltersparadiseesc.com/C...Calculator.php