\[\boxed{\mathbf{1029\ (1029)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\textbf{а)}\ S = 3 \bullet 5 + \frac{1}{2} \bullet 1 \bullet 5 + \frac{1}{2} \bullet 1 \bullet 5 = 3 \bullet 5 + 1 \bullet 5 = 15 + 5 = 20\ (кв.\ ед.).\]
\[2)\ S = \frac{1}{2} \bullet 4 \bullet 6 = \frac{24}{2} = 12\ кв.\ ед.\]
\[3)\ S = 2 \bullet 5 + \frac{1}{2} \bullet 5 \bullet 2 + \frac{1}{2} \bullet 5 \bullet 2 = 2 \bullet 5 + 5 \bullet 2 = 2 \bullet 10 = 20\ кв.\ ед.\]
\[Ответ:а)\ 20\ кв.\ ед.;\ \ б)\ 12\ кв.\ ед.;\ \ в)\ 20\ кв.\ ед.\]