Решебник по геометрии 7 класс Атанасян ФГОС Задание 582

 

\[\boxed{\mathbf{582.ОК\ ГДЗ - домашка\ на}\ 5}\]

\[Рисунок\ по\ условию\ задачи:\]

\[\mathbf{Дано:}\]

\[\mathrm{\Delta}ABC\sim\mathrm{\Delta}A_{1}B_{1}C_{1};\]

\[AC = 42\ м;\]

\[A_{1}C_{1} = 6,3\ см;\]

\[A_{1}B_{1} = 7,2\ см.\]

\[\mathbf{Найти:}\]

\[AB - ?\]

\[\mathbf{Решение.}\]

\[1)\ \mathrm{\Delta}ABC\ \sim\mathrm{\Delta}A_{1}B_{1}C_{1}\ \]

\[(по\ условию):\]

\[\frac{\text{AB}}{A_{1}B_{1}} = \frac{\text{BC}}{B_{1}C_{1}} = \frac{\text{AC}}{A_{1}C_{1}} = k.\]

\[2)\ \frac{\text{AB}}{7,2} = \frac{4200}{6,3}\]

\[AB = \frac{4200 \bullet 7,2}{6,3} = 4800\ см.\]

\[AB = 4800\ :100 = 48\ м.\]

\(Ответ:AB = 48\ м.\)

\[\boxed{\mathbf{582.еуроки - ответы\ на\ пятёрку}}\]

\[\textbf{а)}\ a = 12;c = 13:\]

\[b^{2} = 169 - 144 = 25\]

\[b = 5.\]

\[\textbf{б)}\ a = 7;c = 9:\]

\[b^{2} = 81 - 49 = 32\]

\[b = \sqrt{32} = 4\sqrt{2}.\]

\[\textbf{в)}\ a = 12;c = 2b:\]

\[b^{2} = 4b^{2} - 144\]

\[3b^{2} = 144\]

\[b^{2} = 48\]

\[b = 4\sqrt{3}.\]

\[\textbf{г)}\ a = 2\sqrt{3};c = 2b:\]

\[b^{2} = 4b^{2} - 12\]

\[3b^{2} = 12\]

\[b^{2} = 4\]

\[b = 2.\]

\[\textbf{д)}\ a = 3b;c = 2\sqrt{10}:\]

\[b^{2} = 40 - 9b^{2}\]

\[10b^{2} = 40\]

\[b^{2} = 4\]

\[b = 2.\]