MEASUREMENT OF A CIRCLE
55
The series of values found by Archimedes are shown in the
following table:
a
h
c
n
a
265
306
153
0
1351
571
> [ V(571 2 + 153 2 )]
153
i
2911
> 591|
1162|
>|V{(1162|) 2 + 153 2 }]
153
2
59241 *
>1172|
1823 [
2334|
>[V{(2334i) 2 + 153 2 }]
153
3
i
3661 X 9 T
> 2339-J
1007 [
4673i
153
4
(
2016|f-
h
1560
c V(2911 2 + /
< 3013i \
: V(1823 2 + 2
< 1838 X 9 X
-/(1007 2 + 6i
< 1009|
V {(2016^) 2 -
< 20171
c
780
780
240 f
66
and, bearing in mind that in the first case the final ratio
a 4 : c is the ratio OA : AG = 2 OA : GH, and in the second case
the final ratio h i : c is the ratio AB: BG, while GH in the first
figure and BG in the second are the sides of regular polygons
of 96 sides circumscribed and inscribed respectively, we have
finally
96 X 153 96 x 66
46731 > 77 > 20171 ‘
Archimedes simply infers from this that
3i >7T > 3lf.
As a matter of fact
96 x 153
4673i
= 3
667^
4673| 5
and
667 ^ _ i
4672| 7 ‘
It is also to be observed that 3^ x = 3 + — ? and it may
have been arrived at by a method equivalent to developing
the fraction in the form of a continued fraction.
2017i
It should be noted that, in the text as we have it, the values
of h x , 6 2 , h 3 , h i are simply stated in their final form without
the intermediate step containing the radical except in the first
* t Here the ratios of?« to c are in the first instance reduced to lower
terms.