Originally Posted by
Cedar
I'm just starting to dip my toe into triangles and wanted to try drawing out a block and making it (there's only so many 8" blocks online). I'm new enough to sewing that my triangles and seams are imperfect even if the measurements are right and I don't even feel like I should know what good triangles should look like mid-piecing.
I understand that adding 7/8 to triangles pre-piecing is "correct" but I have no clue where the extra 3/8 goes and how an almost 2" triangle becomes 1", especially if my seams have an 1/8 margin of error (because they probably do).
Can anyone explain why this works and how to tell if you're on track during the piecing process?
Cedar. It is a simple fact of geometry something to do with angles and length. I don't remember why (was over 46 years ago I took a class in geometry) just that it is a fact of life. Just keep it simple and round up an 1/8" then trim after you have pressed them. Have fun.