I would line up the centre V with the pieced block and you can see the dashed line is your 1/4" seam allowance. By using this specialty ruler you get a perfect square, no points cut off! But no specialty ruler is going to work unless your original cutting and sewing is straight and precise.
Okay, you have trimed all your pieced blocks, what can be do with them. I have a few photos of blocks that I have placed on the cutting mat.
You would have some great secondary patterns by sewing them this way.
I will leave you with this and will hopefully have more to show you later in the week.
Take a look at our workshop listings, a nice selection of classes are on offer as well as some quilt weekends. Treat yourself to some fun and bring a friend along!