Question 799786
Find the length of the longest stick you can put in a cube if it has an edge of 10 inches.
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It's the Pythagorean Theorem applied twice.
Call one side the floor.  The diagonal of the floor = {{{sqrt(10^2 + 10^2)}}}
= {{{sqrt(200)}}}
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Then, from either corner to the corner on the ceiling, it's
{{{s = sqrt(200 + 10^2) = sqrt(300)}}}
= {{{10sqrt(3)}}}
=~ 17.32 inches.
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You can do it one move,
{{{d = sqrt(L^2 + W^2 + H^2)}}}
For a cube, {{{d = sqrt(3s^2) = s*sqrt(3)}}}