Question

Fie triunghiul ABC,AB=10cm, AC=20cm, D apartine(AB), DE || BC, E apartine(AC), AD=3cm,AM=15cm,unde AM este mediana dusa din A.
a) Calculati EC;
b) Aratati ca AN=4,5cm,unde {N}=[DE] intersectat [AM].
Va rog da ma ajutati..

Answer 1

AD/AB =AE/AC =AM/AM

AB/AB /AE/AC ;  3/10=AE/20
AE =2*20/10 =6 cm
 AD/AB =AN/AM  ;   3/10 =AN/15
AN =3*15/10 =45/10 =4.5 cm