Answer:
[tex]16.2\ cm[/tex]
Step-by-step explanation:
we know that
The diagonal of a cube is equal to
[tex]D=b\sqrt{3}[/tex]
where
b is the length of an edge of the cube
we have
[tex]D=28\ cm[/tex]
substitute
[tex]28=b\sqrt{3}[/tex]
[tex]b=28/\sqrt{3}=16.2\ cm[/tex]
