\[Страница\ 41.\]
\[\boxed{\mathbf{1}.}\]
\[S = 10\ дм^{2}.\]
\[S = 10\ дм^{2}.\]
\[S = 16\ дм^{2}.\]
\[\boxed{\mathbf{2}.}\]
\[\textbf{а)}\ 5\ см\ и\ 14\ см:\]
\[S = 5 \cdot 14 = 70\ см^{2}.\]
\[\textbf{б)}\ 15\ см\ и\ 40\ мм = 4\ см:\]
\[S = 15 \cdot 4 = 60\ см^{2}.\]
\[\textbf{в)}\ 13\ м = 130\ дм\ и\ 7\ дм:\]
\[S = 130 \cdot 7 = 910\ дм^{2}.\]
\[\textbf{г)}\ 68\ см\ и\ 5\ м\ 9\ см = 509\ см:\]
\[S = 509 \cdot 68 = 34\ 612\ см^{2}.\]
\[\boxed{\mathbf{3}.}\]
\[\textbf{а)}\ n = 16 - целых\ клеток;\]
\[\textbf{б)}\ k = 6 - половинок;\]
\[k\ :2 = 6\ :2 = 3.\]
\[\textbf{в)}\ n + k\ :2 = 16 + 3 = 19\ см^{2}.\]