When you buy the whole set of rulers you can handle anything - use the one closest to the size block you are making.
I regularly use all sizes of my rulers working on the same project.
Complete Set - Everyday Expert Rulers - All sizes
Rulers included - 4 1/2"; 7 1/2"; 12 1/2";
Save money by buying the complete set.
Make perfect Half-Square Triangles, Hourglass blocks and Flying Geese.