\[Страница\ 68.\]
\[\boxed{\mathbf{10.}}\]
\[\boxed{\mathbf{11.}}\]
\[Пятиугольник:\]
\[\boxed{\mathbf{12.}}\]
\[\angle A = 65{^\circ};\ \ \ \ \ \]
\[\angle C = 30{^\circ};\ \ \ \ \ \ \]
\[\angle B = 85{^\circ}.\]
\[Сумма\ углов\ равна\ 180{^\circ}.\]