SOLUTION: Good day! Can you please help me solve this problem? Find the length of a diagonal of a regular octahedron if its edges measure 5 cm. Thank you very much!

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Question 1001900: Good day! Can you please help me solve this problem?
Find the length of a diagonal of a regular octahedron if its edges measure 5 cm.
Thank you very much!

Answer by ikleyn(52780) About Me  (Show Source):
You can put this solution on YOUR website!
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Find the length of a diagonal of a regular octahedron if its edges measure 5 cm.
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A regular octahedron with the edge measure  5 cm  is shown in the  Figure  below.


Figure. A regular octahedron

It has  8  faces,  each of which is a regular triangle.  All edges of a regular octahedron are congruent
(have the same measure).

You can imagine a regular octahedron as comprised of two rectangular pyramids whose two square bases are joined
and overposed each to the other.

Notice that the horizontal section of a octahedron  (as it is shown in the Figure)  is a square.
The vertical section of a octahetron is a square too.  These squares are congruent and have the same side measures.

A diagonal of octahedron is a diagonal of one of these two square.
Thus octahedron has  4  diagonals,  and these diagonals have the same measure.

So,  this measure is  a%2Asqrt%282%29,  where  a  is the measure of the octahedron edge.

In your case the measure of the octahedron diagonals is  5%2Asqrt%282%29 cm.

See also  this article  from Wikipedia.