\[\boxed{\mathbf{563.еуроки - ответы\ на\ пятёрку}}\]
\[Рисунок\ по\ условию\ задачи:\]
\[\mathbf{Дано:}\]
\[ABCD - квадрат;\]
\[EFMN - ромб;\]
\[P_{\text{ABCD}} = P_{\text{EFNM}}.\]
\[\mathbf{Сравнить:}\]
\[S_{\text{ABCD}}\ и\ S_{\text{EFNM}}.\]
\[\mathbf{Решение.}\]
\[1)\ S_{\text{ABCD}} = AB^{2};\]
\[S_{\text{EFNM}} = MN \bullet EH.\]
\[2)\ P_{\text{ABCD}} =\]
\[= AB + BC + CD + AD = 4 \bullet AB;\]
\[P_{\text{EFNM}} =\]
\[= FE + FN + NM + EM =\]
\[= 4 \bullet EM;\]
\[Отсюда:\]
\[AB = EM.\]
\[4)\ EM^{2} > EM \bullet EH;\]
\[S_{\text{ABCD}} > S_{\text{EFNM}}.\]
\[Ответ:S_{\text{ABCD}} > S_{\text{EFNM}}.\]