номер 240 гдз 8 класс алгебра Муравин Муравин

1)\begin{equation}\pi - иррац.число \end{equation} \begin{equation}C=2\pi R \end{equation}
и \begin{equation}S=\pi R^{2} \end{equation} \begin{equation}\sqrt{\pi }=1,772... \end{equation} \begin{equation}3\cdot \sqrt{\pi }=3\cdot 1,772...=5,316... \end{equation}
2)\begin{equation}S=2\pi R^{2} \end{equation} \begin{equation}R^{2}=\frac{S}{\pi } \end{equation} \begin{equation}R=\sqrt{\frac{S}{\pi }} \end{equation}
3)\begin{equation}S=\pi \left ( \frac{d}{2} \right )^{2}=\pi \frac{d^{2}}{4} \end{equation} \begin{equation}S=\frac{\pi d^{2}}{4} \end{equation}
d - ? \begin{equation}4S=\pi d^{2} \end{equation} \begin{equation}d^{2}=\frac{4S}{\pi } \end{equation} \begin{equation}d=\sqrt{\frac{4S}{\pi }} \end{equation}
4) a) \begin{equation}S=36\pi мм^{2} \end{equation} \begin{equation}d=\sqrt{\frac{4\cdot 36\pi }{\pi }}=\sqrt{4\cdot 36}=2\cdot 6=12мм \end{equation}
б)\begin{equation}S=81\pi см^{2} \end{equation} \begin{equation}d=\sqrt{\frac{4\cdot 81\pi }{\pi }}=\sqrt{4\cdot 81}=2\cdot 9=18см \end{equation}
в)\begin{equation}S=7\pi дм^{2} \end{equation} \begin{equation}d=\sqrt{\frac{4\cdot 7\pi }{\pi }}=\sqrt{28}=5,29...(дм) \end{equation}
г)\begin{equation}S=13\pi м² \end{equation} \begin{equation}d=\sqrt{\frac{4\cdot 13\pi }{\pi }}=\sqrt{52}=7,21м \end{equation}
Play
Play
previous arrow
next arrow
Slider