By the Pythagorean Theorem:
d^2=x^2+y^2, where x and y are the dimensions of the rectangle, however this is just a square, so x=y=s so
d^2=s^2+s^2
d^2=2s^2, and we are told that s=6 so
d^2=2(6^2)
d^2=2(36)
d=√(2(36))
d=6√2 units
d≈8.49 units (to nearest hundredth of a unit)
