\[\boxed{\mathbf{44.}ОК\ ГДЗ\ –\ домашка\ на\ 5}\]
\[Дано:\]
\[OB \parallel CD;\]
\[AO\ и\ CD - скрещиваются.\]
\[Решение.\ \]
\[\textbf{а)}\ \angle AOB = 40{^\circ};\ \ CD \parallel OB:\]
\[\angle\ между\ \text{AO\ }и\ CD = 40{^\circ}.\]
\[\textbf{б)}\ \angle AOB = 135{^\circ}:\]
\[\angle между\ \text{OA\ }и\ OB = 45{^\circ};\]
\[\angle между\ \text{OA\ }и\ CD = 45{^\circ}.\]
\[\textbf{в)}\ \angle AOB = 90{^\circ}:\]
\[\angle между\ OA\ и\ CD = 90{^\circ}.\]
\[Ответ:а)\ 40{^\circ};б)\ 45{^\circ};в)\ 90{^\circ}.\]