12.
a)AF=BC+DE=36 cm
P=16+15+21+9+36=97 cm
Construim latura CM, M∈AF, CM=AB=16 cm
AM=BC=15 cm
MF=DE=21 cm
MD=EF=9 cm
A=Aria dreptunghi ABCM + Aria dreptunghi MDEF
=(16x15)+(21x9)
=240+189
=429 cm²
b)PQ=SR-NO-LM=15 cm
P=4+5+10+10+15+4+30=78 cm
A=Aria patrat MNOP + Aria dreptunghi LSRQ
=(MN)²+(SRxRQ)
=100+120
=220 cm²