9514 1404 393
Answer:
9√6 units
Explanation:
You know that the diagonal of a square is √2 times the length of one side, so the diagonal of your square is ...
diagonal = (√2)·side
diagonal = √2·9√3 = 9√(2·3)
diagonal = 9√6
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In case you hadn't committed that relationship to memory, you could figure it out from the Pythagorean theorem:
d² = s² + s²
d² = 2s² . . . combine terms
d = s√2 . . . take the square root