$\textit{About the question:}$

`Find the angle between the body diagonals of a cube.`

Which of the two solution is preferred? (The smaller, or larger angle?)

Question

$\textit{About the question:}$

`Find the angle between the body diagonals of a cube.`

Which of the two solution is preferred? (The smaller, or larger angle?)

unklerhaukus · Answer

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unklerhaukus · Answer

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ganeshie8 · Answer

They are supplementary, so i don't see any major reason to prefer one over the other

unklerhaukus · Answer

s = 71°,  l = 109°

unklerhaukus · Answer

But the question says find `the angle`, they only want one

ganeshie8 · Answer

I think the question must specify what angle to find. It should ask like, `find the "acute angle" ` or `find the "obtuse angle"` etc..

ganeshie8 · Answer

guess i would give the acute angle if the question doesn't ask explicitly

unklerhaukus · Answer

Why go with the acute solution?

ganeshie8 · Answer

no particular reason as of now
i don't even know how to find the acute angle yet, but i think coordinate geometry/vectors will do the job, and the effort seems to be same for both angles

mayankdevnani · Answer

Is it helpful ?
Its my work !

dan815 · Answer

both are right

imqwerty · Answer

i would go with acute angle solution because its relatively little less lengthy to find acute angle than to find the obtuse angle and mostly questions like this have the acute angle as solution..or else they are multiple choice

phi · Answer

I would give the acute angle, based on "convention"... I like small numbers more than big numbers.

unklerhaukus · Answer

It makes senses that the small number is (sufficient) enough to characterize angle between lines

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