Equilateral Triangle Ruler for cutting 3- to 9-inch triangles, measured on a finished side. Measuring with our multiple-size 60-degree rulers is easy! They work perfectly with our hexagon family of templates (Sets G, H and N). Other equilateral triangle rulers measure the height of the triangle from the center of the bottom to the top point. Our rulers measure the triangle on the side. In fact, all From Marti Michell 60-degree family members are size-defined by the length of the finished side because it's the only measurement that is common to all of the shapes in the family.