Question

СРОЧНОЛОООО 3 примера ​

Answer 1

Ответ:

$3)\ \frac{4}{5}$

$4)\ 3,2$

$5) \frac{12}{13}$

Пошаговое объяснение:

$3)\\c=\sqrt{a^2+b^2}=\sqrt{3^2+4^2}=\sqrt{9+16}=\sqrt{25}=5\\\\cos\alpha=\frac{b}{c}=\frac{4}{5}$

$4)\\tg\alpha=\frac{x}{4}\\\\\frac{x}{4}=0,4\ \ \ |\cdot4\\\\x=1,6\\\\S=\frac{4x}{2}=2x=2\cdot1,6=3,2$

$5)\\a=36-2\cdot13=36-26=10\\\\h^2+(0,5a)^2=13^2\\\\h^2+5^2=169\\\\h^2=169-25\\\\h^2=144\\\\h=\sqrt{144}\\\\h=12\\\\sin\alpha=\frac{h}{13}=\frac{12}{13}$