Răspuns:
14,4cm
Explicație pas cu pas:
BD=18, AC=24. AM=10. Cred deacum se știe AB=15.
ΔAMN~ΔCBN, ⇒AM/CB=AN/CN ⇒ 10/15=AN/CN
[tex]\dfrac{10}{15}= \dfrac{AN}{CN} ~=>~\dfrac{10+15}{15}= \dfrac{AN+CN}{CN} ~=>~\dfrac{25}{15}= \dfrac{AC}{CN} ~=>~\dfrac{5}{3}= \dfrac{24}{CN} ~=>~[/tex]
CN=(3·24)/5=(6·24)/10=144/10=14,4cm.
