This 60 Degree equilateral triangle ruler is great for many projects. Measuring with this multiple size 60 degree ruler is easy. Other equilateral triangle rulers measure the height of the triangle from the center of the bottom to the top point. All of the 60-degree family members are size-defined by the length of the finished side. We made this decision for quilt making projects because the finished side is the only measurement that is common to all of the shapes in the family. Makes finished size triangles from 2in up to 6in.