How to teach paper-folding and cutting: a practical manual-training aid (1892)
[Litchfield, Norma MacLeod] [from old catalog] · Lebanon, Ohio, March brothers · leaf 87
) Then take the intersection of arcsas a central point, and the length of the bases of thetriangles as a radius. … When the triangles forming the sides and base ofa triangular pyramid are all equilateral, the pyramidis called an equilateral triangular pyramid. See fig-ure No. 125. The next figure shows the plan forthis solid. It is very simple, and requires no specialexplanation. Draw the large triangle first,…
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