SOLUTION: What is the length of the diagonal of the largest cube that can be cut from a right circular cylinder of radius r and height r ?

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Question 1019491: What is the length of the diagonal of the largest cube that can be cut from a right circular cylinder of radius r and height r ?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's first solve for the largest square that can be cut from a circle of radius r.
The diameter of the circle becomes the diagonal of the square so you can solve for the side of the square since the diagonal is (using the Pythagorean theorem),
D%5Bs%5D%5E2=s%5E2%2Bs%5E2
D%5Bs%5D%5E2=2s%5E2
D%5Bs%5D=sqrt%282%29%2As
2r=sqrt%282%29%2As
s=%282r%29%2Fsqrt%282%29
s%5E2=%284r%5E2%29%2F2=2r%5E2
So to make a cube, use that same distance s.
So a diagonal for a cube of side s would be,
D%5Bc%5D=sqrt%28s%5E2%2Bs%5E2%2Bs%5E2%29
D%5Bc%5D=sqrt%283%29%2As
D%5Bc%5D=sqrt%283%29%28%282r%29%2Fsqrt%282%29%29
D%5Bc%5D=sqrt%286%29%2Ar