MATHEMATICS AND ORIGAMI

Mathematics and Origami

10.1.4 PENTAGON WITH A PREVIOUS FOLDING

Process shown in figs. A is common to pentagon, hexagon, heptagon and octagon.

The process comprising the ten figs. B is specific for the pentagon and starts from last

fig. A. This process B leads to an imperfect pentagon.

Fig. C contains all the elements from B which are necessary to easily evaluate that im-

perfection. Since that evaluation is rather cumbersome and in order not to bore the reader, we

shall present just the final results. Taking GH as base of the pentagon, we have:

Angle in V, opposite to the base: 112,5º

Adjacent angles to the base, congruent to each other and measuring 110,395º

The other two angles are also congruent to each other, but with a value of 103,355º.

8 7 6 5

A

5 5

O

F E

C

F

O

C

5

E

A

H

G

O

G

H

A

C

E

7 6

A O

7

6

5

A

5 6

O A O

7

A O

6

5

A

O

I

J

I J

I

J

I

J

B

V

B

G H