Question

Помогите с геометрией 8 класс

Answer 1

Ответ:

Объяснение:

$1) S = \frac{1}{2} ab*sin\alpha = \frac{1}{2} *4*6*\frac{\sqrt{2} }{2} = 6\sqrt{2}\\2) S = \sqrt{p(p-a)(p-b)(p-c)} , p = \frac{a+b+c}{2} = \frac{13+14+15}{2} = 21\\ S = \sqrt{21(21-13)(21-14)(21-15)} = \sqrt{21*8*7*6} =\sqrt{7056} =84\\3) \frac{8}{sin90} = \frac{x}{sin30} \\8 = \frac{x}{0,5} ; x = 4\\y = \sqrt{64 - 16} = \sqrt{48} = 4\sqrt{3} \\S = \frac{1}{2} *x*y = \frac{1}{2} *4 *4\sqrt{3} = 8\sqrt{3}$$4) Osnovanie- treugolnika = x:\\ \frac{x}{2} = \sqrt{25-16} = \sqrt{9} = 3 \\x = 6\\\\S = \frac{1}{2} * h * x = \frac{1}{2} * 4 * 6 = 12\\5) - ?\\6) S = a* h = 5 * 8 = 40\\7) S = a * b * sin\alpha = 6 * 6 * \frac{\sqrt{2} }{2} = 18\sqrt{2} \\8) S = h\frac{a + b}{2} = 2 * \frac{3 + 4}{2} = 7\\9) - ?\\10) S = MN * BH = 7 * 3 = 21$