Răspuns:
Explicație pas cu pas:
5. BC=12
Daca m(∡c)=30°⇒ AB=6 si 2AD=AC
Aplicam Pitagora in ΔABC
BC²=AB²+AC²
AC²=144-36=108
AC=6√3⇒ AD=3√3
Aplicam in ΔABC teorema catetei
AB²=BD×BC
36=BD×12
BD=3⇒CD=12-3=9
[tex]A_{ABD}=\frac{AB\cdot BD}{2} =\frac{9\sqrt{3} }{2}[/tex]
[tex]A_{ACD}=\frac{AD\cdot CD}{2} =\frac{27\sqrt{3} }{2}[/tex]
[tex]\frac{A_{ABD}}{A_{ACD}} =\frac{1}{3}[/tex]
6.
4×4+3×4+12×4=16+12+48=76dm
