\[\boxed{\mathbf{555.еуроки - ответы\ на\ пятёрку}}\]
\[\textbf{а)}\ a = 15\ см;h = 12\ см:\]
\[S = 15 \bullet 12 = 180\ см^{2}.\]
\[\textbf{б)}\ S = 34\ см^{2};h = 8,5\ см:\]
\[a = S\ :h = 34\ :8,5 = 4\ см.\]
\[\textbf{в)}\ S = 162\ см^{2};\ h = \frac{1}{2}a:\]
\[S = ah = a \bullet \frac{1}{2}a = \frac{1}{2}a^{2} =\]
\[= 162\ см^{2}\]
\[a^{2} = 324\]
\[\ a = 18\ см.\]
\[\textbf{г)}\ S = 27;h = 3a:\]
\[S = a \bullet h = 3a^{2} = 27\]
\[a^{2} = 9\]
\[a = 3.\]
\[h = 3a = 3 \cdot 3 = 9.\]