C

The lengths of a cuboid edges form $3$ consecutive terms of a geometric sequence. The volume of the cuboid is $140608{\mathrm{cm}}^3$, the sum of its shortest and its longest edge is $221\mathrm{cm}$. Find the length of its shortest edge.

A cube $ABCDEFGH$ with an edge length of $2$ is placed in a coordinate system (see the picture). Let $p$ be a line of intersection of planes $\alpha$ and $\beta$, where $\alpha$ is passing through $C$, $F$ and $H$ and $\beta$ is passing through $A$, $F$ and $H$. Find the parametric equations of the line $p$ and calculate the angle $\phi$ between planes $\alpha$ and $\beta$ . Round $\phi$ to the nearest minute.

A cube $ABCDEFGH$ with an edge length of $2$ is placed in a coordinate system (see the picture). Let the point $M$ be the centre of the edge $EF$. Find the general form equation of the plane $\rho$ passing through the points $B$, $D$, and $G$ and calculate the distance of $M$ from the plane $\rho$.

A straight line $p$ is given by the points $M=[4;3;2]$ and $N=[8;0;5]$ (see the picture). Find the parametric equations of the line $p^{\prime }$ that is symmetrical to the line $p$ in the plane symmetry across the coordinate $xz$-plane.