Question

Помогите пжлст срочно!
608 задача. Даю 20б

Answer 1

1) $cos(D) = \frac{DE}{DF} \\\frac{x}{18} =\frac{2}{9} \\9x=36\\x=4$

2) $cos(F)=\frac{EF}{DF} \\\frac{3.5}{x} =0.7\\0.7x=3.5\\x=3.5/0.7=5$

3) $tg(D)=\frac{EF}{DE} =\frac{11}{12}\\ \frac{x}{1.2}=\frac{11}{12}\\12 x=13.2\\ x=12/13.2=0.9$