\(P = 154\ дм;\ a = 43\ дм;\)
\[b = P\ :2 - a = 154\ :2 - 43 =\]
\[= 77 - 43 = 34\ дм.\]
\[S = ab = 43 \cdot 34 = 1462\ дм^{2}.\]
\[Ответ:1462\ дм^{2},\ 34\ дм.\]