Question 212044
Let the side of the square be s.
{{{A = s^2}}} and...
{{{P = 2(s+s)}}} but...
{{{A = P}}} so...
{{{s^2 = 2(2s)}}} Simplify.
{{{s^2 = 4s}}} Divide both sides by s.
{{{s = 4}}}
The length of each side is 4.
Check:
{{{A = s^2}}} 
{{{A = 4^2}}}
{{{A = 16}}}
{{{P = 2(s+s)}}}
{{{P = 2(4+4)}}}
{{{P = 2(8)}}}
{{{P = 16}}}