3)
[tex]\it Din\ enun \c{\it t}\ \Rightarrow\ BC=1m,\ \ AB=1m,\ \ BE=1,5-1=0,5m\\ \\ \\ CD||AE\ \Rightarrow \Delta AEF\ \sim\ \Delta BEC \Rightarrow \dfrac{AE}{BE}=\dfrac{AF}{BC} \Rightarrow \dfrac{1,5}{0,5}=\dfrac{AF}{1} \Rightarrow\\ \\ \\ \Rightarrow AF=\dfrac{\ \ 1,5^{(10}}{0,5}=\dfrac{15}{5}=3m[/tex]
4)
Transformăm lungimile laturilor în hm, adică:
AC=3hm, AB=4hm, BC=5hm.
[tex]\it Not\breve am\ AD=x,\ BD=y\ \Rightarrow CD=5-y[/tex]
Scriem egalitatea celor două perimetre:
[tex]\it x+y+4=x+5-y+3 \Rightarrow 2y=4 \Rightarrow y=2\ hm[/tex]
[tex]\it \mathcal{A}_{ABD} =\dfrac{1}{2}AB\cdot BD\cdot sin B = \dfrac{1}{2}\cdot4\cdot2\cdot\dfrac{3}{5}=\dfrac{12}{5}=2,4\ hm^2=24000m^2[/tex]
