Mathematics and Origami
Let L and l be the greater and smaller side of the rectangle finally obtained in step 5.
In 2 : CB =
2
L
; CB = CD = AD – AC ; AD = 2 ; AC = AE = 1. therefore
2 1
2
= −
L
In 4: FB = l ; FB = HG = AD – 2AH ; AH = HF =
2
L
. So
l = 2 −L
Then,
( ) ( )
()
2
2 2 2 1
2 2 1
2
2 2 1
=
− −
−
=
−
−
=
I L
L
6.6.4 DIN A FROM ANY RECTANGLE
IF AB = 1, then AE = AD = 2
ABCD ≡ DIN A
If a DIN A4 is wanted, AB should measure 210 mm.
6.6.5 DIN A FROM ANOTHER DIN A
A4 ≡ 297 x 210 ≡ 210 2 x 210
A5 ≡
2
297
210 × ≡ 210
2
210 2
×≡ 210
2
210
×
(^45)
A F
B
G
D
H
3
A D
1
B
2
E
C
discard