Find the length of each side of the polygon for the given perimeter. p=54 mi

This all depends upon the number of sides your polygon has.  I am assuming it is regular and that all the sides have the same length. If this is true, then the polygon will only be able to have the number of sides that is a factor of 54.  If this is a 27-gon, then each side will measure 2 mi; if this is an 18-gon, then each side will measure 3 mi; is this is a triangle, then each side will measure 18 mi; if this is a hexagon, then each side will measure 9 mi; if this is a 9-gon, then each side will measure 6 mi.  It all depends upon the number of sides you have.  Your answer will be found in the info above, again, assuming this is a regular polygon.