Question 341321
{{{drawing(300,300,-10,10,-10,10,
line(-6,-6,-6,6),
line(-4,-6,6,-6),
line(-4,-4,-4,4),
line(-4,-4,4,-4),
line(-6,6,6,6),
line(6,6,6,-6),
line(4,4,4,-4),
line(-4,4,4,4),
locate(-5.8,0,s1),
locate(-3.8,0,s2),
blue(line(-4,-4,-4,-6)),
blue(line(-4,-6,-6,-6)),
locate(-5.2,-3.7,d),
locate(-5,-6.1,x),
locate(-3.8,-4.5,x),
green(line(-6,-6,-4,-4)))}}}
From the diagram,
{{{P1=4*s1=28}}}
{{{P2=4*s2=20}}}
{{{s1=s2+2x}}}
{{{4s1=4s2+8x}}}
{{{8x=4s1-4s2}}}
{{{8x=28-20}}}
{{{8x=8}}}
{{{x=1}}}
.
.
.
{{{d^2=x^2+x^2=2x^2}}}
{{{d=sqrt(2)x}}}
{{{highlight(d=sqrt(2))}}}