Paragraph 25. In laying out a third-pitch brace or rafter cut (Chapter V., Paragraph 76), lay the steel square on the working face of the material in such a position that the figure on the tongue is equal to one-third of twice the figure on the blade. (See Figure 41.) For illustration, if on the blade you have the figure 12", on the tongue you should have the figure 8" (8 being one-third of twice 12, which is 24). By marking along the blade of the square you could lay out the lower end, or foot, of a third-pitch rafter. By marking along the tongue of the square you could lay out the top cut.

Figure 41.