32/4 is 8, so we know that the lengths of the sides are 8 feet.
Because of this I can safely say that the diagonal of the square is 8√2 feet long.
Here's my proof:
\(c=\sqrt { { 8 }^{ 2 }+{ 8 }^{ 2 } } \\ \\ =\sqrt { 64+64 } \\ \\ =\sqrt { 64\cdot 2 } \\ \\ =\sqrt { 64 } \sqrt { 2 } \\ \\ =8\sqrt { 2 }\)
