Question

Fie un triunghi ABC cu AB=42mm si AC=63mm si punctele D∈(AB, E∈(AC.Stabiliti daca DE||BC , stiind ca:
AD=5,2mm si EC=1,5mm si C∈(AE)
Multumesc!!!

Answer 1

BD=AB-AD=42-5,2=36,8 (mm)
AE=AC-CE=63-1,5=61,5 (mm)

$\frac{AD}{BD}$=$\frac{5,2}{36,8} = \frac{52}{368} = \frac{13}{92}$
$\frac{AE}{CE} = \frac{61,5}{1,5} = \frac{615}{15} = 41$

Cum $\frac{13}{92} \neq 41 => \frac{AD}{BD} \neq \frac{AE}{CE}$ => DE nu e paralel cu BC.