Question 200345
The  diagonal  of  the  square  makes  a  triangle  that  is  ,,45 - 45 - 90  degrees,  
with  sides,,,,,1-1-sqrt2
.
sqrt2 / 3 = 1/x
.
cross  multiply
.
xsqrt2 =3
.
x=3/sqrt2 = 3sqrt2 / 2 = 2.12,,,,,,,therefore  side  =  (3/2) sqrt2
.
check
sqrt(2.12^2 +2.12^2) = 3,,,,,ok