man, did I get that one mixed up, eh?
If you get the wrong triangle on the wrong side, would that make a difference?

I think what gets really confusing is that at the tip, there looks like there is so much overhang when you open it up.
One of the blocks in that Victory quilt, if you trim too soon, it gets really bad ... I think it was the Sky rocket block ... anyway, that graph that Bearisgray uploaded sure takes a lot of questions out of the operation, eh?

this is what it would like opened up

sorry - will try attaching it this time

I always avoided half square triangles because if I cut my pieces the size in the instructions I always ended up with one triangle smaller than the other. An experienced quilter gave me a good tip. Always cut your square a half inch larger than the directions say, then cut your square on the diagonal, sew your triangles together and then press. Using a square ruler line up ruler's diagonal line with your block's diagonal seam and cut the block the size you need. A little bit of extra time but worth it. May in Jersey

I really prefer to cut around a ruler or a template also. It does add just a smidgen of fabric that is "not there" when cutting a square or rectangle on the diagonal.

second side added - note circles for joining clues

opened up - even with graph paper, this ended up a little wonky - but maybe this will give you clues -

marking the seam lines does help - especially at first

notice all the ears - this is when they disappear when you square up the unit

Yes, it does matter which way the rectangles are cut.

The directions do show that they need to be cut in two different directions.

also - using the directions given in the pattern - sew with a scant quarter inch seam - I would suggest about a 3/16"

Your unfinished unit should be about 5-1/4 inches

It will "finish" to about 4-3/4 inches

Your four patches will have the same dimensions