Вычислите площадь сферы, если ее радиус равен:
а) $1\frac{10}{11}$ м;
б) $\frac{7}{11}$ см;
в) $3\frac{1}{16}$ дм;
г) $2\frac{5}{8}$ км.
$S = 4πR^2 = 4 * \frac{22}{7} * (1\frac{10}{11})^2 = 4 * \frac{22}{7} * (\frac{21}{11})^2 = 4 * \frac{22}{7} * \frac{21^2}{11^2} = 4 * \frac{2}{1} * \frac{21 * 3}{11} = \frac{504}{11} = 45\frac{9}{11} (м^2)$
$S = 4πR^2 = 4 * \frac{22}{7} * (\frac{7}{11})^2 = 4 * \frac{22}{7} * \frac{7^2}{11^2} = 4 * \frac{2}{1} * \frac{7}{11} = \frac{56}{11} = 5\frac{1}{11} (см^2)$
$S = 4πR^2 = 4 * \frac{22}{7} * (3\frac{1}{16})^2 = 4 * \frac{22}{7} * (\frac{49}{16})^2 = 4 * \frac{22}{7} * \frac{49^2}{16^2} = 1 * \frac{11}{1} * \frac{49 * 7}{16 * 2} = \frac{3773}{32} = 117\frac{29}{32} (дм^2)$
$S = 4πR^2 = 4 * \frac{22}{7} * (2\frac{5}{8})^2 = 4 * \frac{22}{7} * (\frac{21}{8})^2 = 4 * \frac{22}{7} * \frac{21^2}{8^2} = 1 * \frac{11}{1} * \frac{21 * 3}{8} = \frac{693}{8} = 86\frac{5}{8} (км^2)$
Пожауйста, оцените решение
