1103107002

Let $ABCDEF{A}^{\prime }{B}^{\prime }{C}^{\prime }{D}^{\prime }{E}^{\prime }{F}^{\prime }$ be a regular hexagonal prism with the base edge length of $4\mathrm{cm}$ and the height of $8\mathrm{cm}$. Find the angle between the lines $A^{\prime }{D}^{\prime }$ and $C^{\prime }{D}^{\prime }$ (see the picture).