Let $\overline{\mathrm{a}}, \overline{\mathrm{b}} , \overline{\mathrm{c}}$ be three non-coplanar vectors and $\overline{\mathrm{a}}=\frac{\overline{\mathrm{b}}\times \overline{\mathrm{c}}}{\left[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}\right]},\overline{\mathrm{b}}=\frac{\overline{\mathrm{c}}\times \overline{\mathrm{a}}}{\left[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}\right]},\overline{\mathrm{c}}=\frac{\overline{\mathrm{a}}\times \overline{\mathrm{b}}}{\left[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}\right]}.$ The length of the altitude of the parallelepiped formed by $\overline{\mathrm{a}}, \overline{\mathrm{b}} , \overline{\mathrm{c}}$  as conterminous edges, with respect to the base having $\overline{\mathrm{a}}$ and $\overline{\mathrm{c}}$ as its adjacent sides is