Question 1063946
<pre><b>
Even though there are 9 poles on each side, there are only
8 80-meter spaces between each pair of poles, as you see
below, where the numbers 1 through 9 represent the poles:


 1 80m 2 80m 3 80m 4 80m 5 80m 6 80m 7 80m 8 80m 9

Therefore the square field is 8×80m = 640m of each side.

Since a square has 4 sides, the perimeter is 4×640m = 2560m.

Edwin</pre></b>