Ab=9
BC=4
a)A(ABCD)=9×4=36 cm²
b)
AM=9×1/3=3 cm
DC=AB=9
DN=9×2/3=6 cm
inaltimea trapez=AD=BC=4 cm
Atrapez AMND = (3+6)×4/2=36 cm²
c)
MB=AB-Am=9-3=6 cm
h = 4 cm
A triunghiul MNB =MB×h/2= 6×4/2=12 cm²
A triunghiul MNB =BN×(d(M,BN)/2=12 cm²
5×(d(M,BN)/2=12 cm²
(d(M,BN)=12×2/5=4,8 cm