Rosemarie, make sure you print the foundation piecing pattern “original size” on your printer, (not “fit to page” or “shrink to fit”, depending on your computer). You may need to look for it on your printer.
The other suggestion is: I went out a bought myself a basic geometry set – the sort the kids need for school. All those angle problems solved!
Teens keep asking “Why do I need to learn all this maths?” I tell them “so you can QUILT!”