- The following construction of the golden number is very well-known and very easy to prove:

Given the segment AB,

(1) Erect BC perpendicular to AB.

(2) Find the midpoint D of AB.

(3) Describe an arc with radius DC and D as center, intersecting the ray AB at E.

Then AE/AB = golden number.

Does this construction date back to the greeks? Some reference? - Le 08/03/2011 08:38, Francisco Javier a écrit :
> The following construction of the golden number is very well-known and

You forget to precise AB=BC.

> very easy to prove:

>

> Given the segment AB,

> (1) Erect BC perpendicular to AB.

> (2) Find the midpoint D of AB.

> (3) Describe an arc with radius DC and D as center, intersecting the ray

> AB at E.

> Then AE/AB = golden number.

--

Etienne - Of course, you are right.

--- In Hyacinthos@yahoogroups.com, Etienne Rousee <etienne@...> wrote:

>

> Le 08/03/2011 08:38, Francisco Javier a ï¿½crit :

> > The following construction of the golden number is very well-known and

> > very easy to prove:

> >

> > Given the segment AB,

> > (1) Erect BC perpendicular to AB.

> > (2) Find the midpoint D of AB.

> > (3) Describe an arc with radius DC and D as center, intersecting the ray

> > AB at E.

> > Then AE/AB = golden number.

>

> You forget to precise AB=BC.

>

> --

>

> Etienne

>