In the cube \(ABCDEFGH\) find the
angle between the lines \(S_{AE}S_{HC}\)
and \(S_{HC}S_{BF}\),
where \(S_{AE}\),
\(S_{HC}\) and
\(S_{BF}\) are the centers
of the segments \(AE\),
\(HC\) and
\(BF\),
respectively.
A cuboid has sides \(a = 5\, \mathrm{cm}\),
\(b = 8\, \mathrm{cm}\), and
\(c = \sqrt{111}\, \mathrm{cm}\). Find the length of the cuboid’s space diagonal \(u\) (see the picture).
The side of a regular hexagonal prism
\(ABCDEFA'B'C'D'E'F'\) shown in the picture is
\(a = 3\, \mathrm{cm}\) and the height is
\(v = 8\, \mathrm{cm}\). Find the angle
between the diagonal \(AD'\)
and the base plane \(ABC\)
(round your result to the nearest degree).
The sides of a rectangular box shown in the picture are \(a = 3\, \mathrm{cm}\),
\(b = 4\, \mathrm{cm}\), and
\(c = 12\, \mathrm{cm}\). The space diagonal
is \(u_{t}\) and the longest
face diagonal is \(u_{s}\).
Find the ratio \(u_{t} : u_{s}\).