Originally Posted by
dray965
I'm talking about the half-square triangle.
I'd be willing to bet that 99.99% of the time when someone says "half square triangle" or "HST" they actually mean a triangle square, the square formed by two 45º triangles. In that case, it would definitely be the length of the side of the square.
There was a whole thread about the HST mis-nomer recently.
http://www.quiltingboard.com/main-f1...n-t243673.html