Question 971270

Since all the angles are equal, each direction-change is {{{360/n}}}, and that means that each interior angle is {{{180}}}º minus this amount, or

{{{180 - 360/n }}}

for {{{n=15}}} we will have:
{{{180 -360/15 = 180 -24 = 156}}}º 

then, the sum of all internal angles is: 
{{{ 15*180 - 360=2340}}}

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if one side has a length of {{{5ft}}},and we have {{{15}}} sides, then the perimeter is {{{15*5ft=75ft}}}