Help, Please. Need the formula for a Half Quarter Square (Variation)
 

I already have my quilt pattern drafted and have made my practice blocks, except for one. I need to construct an 8" (finished size) half quarter triange variation. I have included an image to illustrate what I am trying to do. I have a horrible tendency to overthink the simplist things, so I need your help. I would like any help in the form of an easy formula, or the measurements for this size block with accuracy or allowing myself to cut down when I square off. Please keep in mind though that I need to be on the conservative side of saving my fabric (usually I'm not). Thanks in advance.

The "exact" formulas:

For the HST:
Starting squares - add 7/8" to the FINISHED size, cut in half on the diagonal.

For the QST:
Starting squares - add 1.25" to the FINISHED size, cut twice on the diagonal.
However, you can make the HST (draw diagonal, sew either side, cut apart) and then cut that in half.
Depends on how scrappy your color choices - if they're all going to be green and yellow or pairs of colors, then make the HST.

These triangles will all have straight edges on the outside of the blocks - no bias.

I prefer to start with larger squares, make the blocks, and then trim down to the UNFINISHED size.

HTH.

Agree with above.

Thank You, HTH...................

Actually, since I'm incredibly lazy, I would do the first part for the QST's (making the HST's).
But oversizee, like, starting with squares that are at least 9.5".

Then I'd take that HST block, draw a diagonal line - perpendicular to the sewn one - place it on top of a BLUE plain square.

Now sew 1/4" on each side of the line, and cut apart.

That way you don't even have to deal with any bias edges at all.

Then trim both down to perfect 8.5" UNFINISHED blocks.

Obviously, make a sample with some scraps to confirm the above. :mrgreen:

awesome! i so appreciate these tips, thank you! as soon as i read your first reply, MTS, i made a block following your directions, and it worked great and by the time you replied again, i figured out about adding the 1/4". and now it's a bonus with your suggestion in not even having to deal with the bias. thank you. :D

The No Math Method: Draw a block full size, trace the smaller parts with plenty of space in-between and then add the 1/4".