Răspuns:
Explicație pas cu pas:
a) L=28 cm l=L-3=25 cm
A=28·25=700 cm²
P=2(28+25)=106 cm
b) L=27 cm l=27:3=9 cm
A=27·9=243 cm²
P=2(27+9)=2·36=72 cm
c)L=42 cm l=42-7=35 cm
A=42·35=1470 cm²
P=2(42+35)=2·77=154· cm
d) l=14 cm L=2·14=28 cm
A=14·28=392 cm²
P=2(14+28)=2·42=84 cm
e) L=24 cm l=2·24/3=16 cm
A=24·16=384 cm²
P=2(24+16)=2·40=80 cm
f) L=30 cm l=2·30/5=12 cm
A=12·30=360 cm²
P=2(12+30=2·42=84 cm