Question

Se da triunghiul ABC, M apartine (AB) si MN || BC , N apartine (AC). Daca AM=4 cm, AN=3 cm, BC=12 cm si MN=4 cm, aflati perimetrul trapezului BCNM.

Answer 1

Deci, ΔAMN≡ΔABC⇒$\frac{MN}{BC}$ = $\frac{AN}{AC}= \frac{AM}{AB}$ 
$= \frac{4}{12}= \frac{4}{AB}= \frac{3}{AC}$  
$\frac{1}{3}= \frac{4}{AB}$⇒ AB = 4×3÷1=12 
$\frac{1}{3}= \frac{3}{AC}$⇒ AC = 3×3÷1=9 
STIM URMATOARELE DATE: AB=12 AM=4 MN=4 AN=3 BC=12 AC=9 
AB= AM+MB⇒MB=AB-AM=12-4=8⇒ MB=8
AC=AN+NC⇒NC=AC-AN=9-3=6⇒NC=6
P trapezului BCNM= BC+CN+MN+MB= 12+6+4+8= 30
P BCNM= 30 cm 

Sper ca te-am ajutat