First draw a picture (see attached).
You want to find the diagonal of the cube, length AB.
The right triangle formed is trianagle ABD.
AD = 10m
DB will be the hypotenuse of triangle BCD.
.
If we know the length of AD and DB, we can find AB.
In fact, the diagonal of any cube is √3 times the side length of the cube.
Let <em>s</em> be the side length (as in AD or CD in the attached) and
h be the hypotenuse of the base, (DB in the attached) and
<em>d</em> be the diagonal of the cube (AB in the attached).
The hypotenuse of the base will be:
.
The cube's diagonal will be:
.
Substituting
as 
, you have
You want to find the diagonal of the cube, length AB.
The right triangle formed is trianagle ABD.
AD = 10m
DB will be the hypotenuse of triangle BCD.
If we know the length of AD and DB, we can find AB.
In fact, the diagonal of any cube is √3 times the side length of the cube.
Let <em>s</em> be the side length (as in AD or CD in the attached) and
h be the hypotenuse of the base, (DB in the attached) and
<em>d</em> be the diagonal of the cube (AB in the attached).
The hypotenuse of the base will be:
The cube's diagonal will be:
Substituting
