A rectangular box has dimensions 5, 12, and 13. What is the length of the space diagonal of the box?
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Correct answer
A. sqrt(338)
Principle or equation
The space diagonal d of a rectangular box with side lengths a, b, c is d = sqrt(a^2 + b^2 + c^2).
Why this answer is correct
d = sqrt(5^2 + 12^2 + 13^2) = sqrt(25 + 144 + 169) = sqrt(338).
Example
For a box with sides 3, 4, 12, d = sqrt(9 + 16 + 144) = sqrt(169) = 13.
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