This easy to use ruler takes the math out of cutting half-square and quarter-square triangles. It lets you cut both types of triangles from strips, rather than by cutting squares diagonally into triangles. We love using this special ruler for scrap quilts. Because you use strips of even inch or half inch widths, you can cut squares from the same strips that you used for triangles. NOTE-Cutting guide marks on the ruler are for finished size triangles.