Question 957698
<pre>
I'll just tell you how to do it.

The area of the central (isosceles) triangle below is one-fifteenth of the area of
the regular 15-gon.  
The base of that triangle is one-fifteenth of the perimeter of the regular
15-gon.  That is, {{{matrix(1,2,180,"yds.")/15}}} = 12 yds. 
The vertex angle of that isosceles triangle is one-fifteenth of 360°, or 24°.


{{{drawing(400,400,-1.2,1.2,-1.2,1.2,

line(-0.20791169,-0.9781476,0,0),
line(0.20791169,-0.9781476,0,0),
locate(-.16,-1,matrix(1,2,12,"yds.")),

green(line(0,0,0,-0.9781476)),



line(0,1,-0.40673664,0.91354546),
line(-0.40673664,0.91354546,-0.74314483,0.66913061),
line(-0.74314483,0.66913061,-0.95105652,0.30901699),
line(-0.95105652,0.30901699,-0.9945219,-0.10452846),
line(-0.9945219,-0.10452846,-0.8660254,-0.5),
line(-0.8660254,-0.5,-0.58778525,-0.80901699),
line(-0.58778525,-0.80901699,-0.20791169,-0.9781476),
line(-0.20791169,-0.9781476,0.20791169,-0.9781476),
line(0.20791169,-0.9781476,0.58778525,-0.80901699),
line(0.58778525,-0.80901699,0.8660254,-0.5),
line(0.8660254,-0.5,0.9945219,-0.10452846),
line(0.9945219,-0.10452846,0.95105652,0.30901699),
line(0.95105652,0.30901699,0.74314483,0.66913061),
line(0.74314483,0.66913061,0.40673664,0.91354546),
line(0.40673664,0.91354546,0,1) )}}}


Find the area of that triangle and multiply it by 15.
The green line is the height of that triangle.

Edwin</pre>