Question 215359
Since the diagonal of the square is 26 inches, then by letting each side equal S, and using the Pythagorean formula, {{{a^2 + b^2 = c^2}}}, we get: {{{S^2 + S^2 = D^2}}}

{{{2S^2 = 26^2}}} ------- {{{S^2 = 676/2 = 338}}} ---------- {{{S = sqrt(338) = 18.38}}}


Therefore, length of each side, or S = {{{highlight_green(18.38)}}} inches, and perimeter = 4S, or 4(18.38) = {{{highlight_green(73.52)}}} inches.