12)
In ΔABD dr : AB=20cm, ∡A=60 ⇒∡B=30⇒ T∡30 ⇒AD=AB/2⇒
AD= 20/2=10 cm
ABCD paralelogram⇒ AB=CD=20cm si AD=BC=10 cm
Perimetrul ABCD = AB+BC+CD+DA= 20+10+20+10 = 60 cm
11)
MNPQ - paralelogram⇒ MN= PQ = 4dm = 40cm
si NP=MQ =32 cm
P MNPQ = MN+NP+PQ+MQ= 40+32+40+32=72+72=144 cm
