Cube Space Diagonal

d=a3d = a \sqrt{3}

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The space diagonal runs through a cube's interior from one corner to the opposite corner, and two applications of the Pythagorean theorem give its length: the face diagonal is a√2, and combining that with the third edge yields d = a√3 ≈ 1.732a. Practical check: the longest rod that fits inside a 1 m cubic box is about 1.73 m. The relation is linear, so inverting it is a simple division with no branch issues.

Cube Space Diagonal
d=a3d = a \sqrt{3}
Where
  • dd= Space diagonal
  • aa= Edge length
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