MATHEMATICS AND ORIGAMI

Jesús de la Peña Hernández

implies the following proportion between a (height) and b (base):a b

4

3

≥. If a b

4

3

> , an

equilateral triangle of the envelope type (point 8.2.4) is obtained.

8.2.4 EQUILATERAL TRIANGLE OF THE ENVELOPE TYPE
It is evident that the resulting triangle (last in the process) has a side half of that in the starting
square. The reader may observe that details of folding are not specified any more; e.g. we have
obviated the description of folding in Fig. 3 as:
C → AB; D → D

7

(^89)
10 11
(^123)
6 5 4