§ Стр. 137
\[Страница\ 137.\]
\[\boxed{\mathbf{15.}}\]

\[BD = B_{1}D_{1}.\]
\[\boxed{\mathbf{16.}}\]
\[1)\]

\[2)\ \]

\[\boxed{\mathbf{17.}}\]

\[Страница\ 137.\]
\[\boxed{\mathbf{15.}}\]

\[BD = B_{1}D_{1}.\]
\[\boxed{\mathbf{16.}}\]
\[1)\]

\[2)\ \]

\[\boxed{\mathbf{17.}}\]
