Question 199275
Hi there,


The trick to this problem is to use the Pythagorean theorem. However, you need to use it twice (since we've moved into 3 dimensions). It's hard to explain why (let alone draw it), so I thought that this <a href="http://mathcentral.uregina.ca/QQ/database/QQ.09.04/brett1.html"page</a> would do. Let me know if it makes sense.



It turns out that for a cube with side "x", the length of the diagonal is {{{d=x*sqrt(3)}}}




So in this case, the length of the side is 10 cm. So plug x=10 into {{{d=x*sqrt(3)}}} to get {{{d=10*sqrt(3)}}} which approximates to {{{x=17.32}}}



So the length of the diagonal is about 17.32 cm long.