You can put this solution on YOUR website! what is the length of the diagonal of a square with area 40.5 square inches?
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Draw the picture.
Let each side of the square be "x".
Then x^2=40.5
Then, diagonal^2 = side^2 + side^2
diagonal^2 = 40.5 + 40.5 = 81
diagonal = 9 inches
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Cheers,
Stan H.