\[1)\ 3,\ \ \ 8,\ \ \ 11,\ \ \ 6.\]
\[Пусть\ одна\ часть\ равна\ x:\]
\[\angle A = 3x;\ \ \ \angle B = 8x;\]
\[\angle C = 11x;\ \ \ \angle D = 6x;\]
\[\angle A + \angle C = 14x;\ \ \ \]
\[\angle B + \angle D = 14x;\]
\[\angle A + \angle C = \angle B + \angle D = 180{^\circ}.\]
\[Ответ:\ \ да.\]
\[2)\ 4,\ \ \ 5,\ \ \ 4,\ \ \ 2.\]
\[Пусть\ одна\ часть\ равна\ x:\]
\[\angle A = 4x;\ \ \ \angle B = 5x;\]
\[\angle C = 4x;\ \ \ \angle D = 2x;\]
\[\angle A + \angle C = 8x;\ \ \ \]
\[\angle B + \angle D = 7x;\]
\[\angle A + \angle C \neq \angle B + \angle D \neq 180{^\circ}.\]
\[Ответ:\ \ нет.\]