Question 1207594
<pre>
The formulas you need are:

{{{system(n=matrix(1,3, number,of,sides),

a=apothem=matrix(1,2,10,feet),
s=matrix(1,2,side,length)=2*a*tan(180^o/n^""),
A=expr(1/2)(n*s*a)=matrix(1,3,500,square,feet),P=perimeter=n*s,
matrix(1,3,Cost,of,fence)="$7.50"*P)}}}

Note: apothem = little "a",  Area = capital "A", don't confuse them!

Edwin</pre>