Question

AJUTOR 20 pcteeee ex 3

Answer 1

     
$a) \\ A = \frac{c_1*c_2}{2}= \frac{4*5}{2} =\frac{20}{2}=\boxed{10\;cm^2} \\ \\ b) \\ \frac{DC}{AC}= \frac{1}{3} \;\;=\ \textgreater \ \;\; \frac{AC}{BC}= \boxed{\frac{1}{3}}\;\;\;\text{deoarece sunt triunghiuri asemenea.} \\ \\ c) \\ \text{Raza cercului circumscris triunghiului dreptunghic} \\ \text{este egalacu jumatate din ipotenuza} \\ \\ R= \frac{ \sqrt{AB^2+AC^2} }{2}=\frac{ \sqrt{6^2+8^2} }{2} = \frac{ \sqrt {36+64} }{2}=\frac{ \sqrt {100} }{2}= \frac{10}{2}=\boxed{5\;cm}$