"Guess who" wrote in message
...

The general formula for the chord length, or side of the polygon, is C
= D*sin(180/N) [angle in degrees] where D is the diameter, and N is
the number of sides.

For N = 10, D = 72", you have C = 72*sin(18)

On the calculator use the following order of keypress:

18
sin
x
72
=

Ans: 22.249...

Now subtract 22

-
22
=

Now change the decimal to 16ths

x
16
=
Ans: 3.98...

That is, about 4-16ths, or 1/4"

So .... 22 1/4", near as dammit is to swearing.


You might want to reread the question. The diameter is 36" not 72".