This is the way I look at it also.

Your question is not at all ridiculous. Triangles come in all shapes and sizes, and I would not automatically assume that you meant a HST, but since you do, I would agree with the others who would generally refer to it by the size of the finished square. For 60 degree (equilateral) triangles, there are actually differences in how rulers are made to measure them. Some measure from the base to the tip, and others measure the sides. http://www.frommarti.com/mm5/merchan...ategory_Code=R

I agree. Usually, if I talked about a 2" finished half square triangle, it is the finished side of the triangle and NOT the diagonal edge. BUT you have to be careful remembering to ask the quilters if that is the finished or unfinished size. I have no ideal what the diagonal edge of an unfinished 2.5 measures.

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

For Half Square Triangles, you measure the side cut on the straight or cross grain of the fabric....or the short side of the triangle in this case. (The long side is cut on a diagonal.)

Jan in VA

Thanks for everyone's responses! I appreciate the info, now I won't feel ignorant when asking about them.

Here's a link to calculate the hypotenuse of a triangle: https://www.google.com/webhp?sourcei...ght%20triangle

Yep, I agree, the finished size of the half square triangle block...dray965 the only question to be embarrassed about is the one you don't ask...good question! :)

I love this interactive site for calculating the diagonal of a triangle.

http://www.mathopenref.com/squarediagonals.html

This is a question to which we do not need to know the answer. I'm glad about that.