\[x{^\circ} - \angle B;\ \ 3x{^\circ} - \angle A;\ \ 6x{^\circ} - \angle C\]
\[x + 3x + 6x = 180\]
\[10x = 180\ \ \ \]
\[x = 18{^\circ}\ \ \ \ \]
\[\angle A = 3 \bullet 18 = 54{^\circ}\ \ \ \ \]
\[\angle C = 6 \bullet 18 = 108{^\circ}\]
\[Ответ:\angle A = 54{^\circ};\angle B = 18{^\circ};\]
\[\angle C = 108{^\circ}.\]