5.P=60+L
L=3l
P=60+3l
2L+2l-3l=60
6l+2l-3l=60
5l=60, l=60:5=12
L=3x12=36
p=P:2=L+l=36+12=48
7. l=200:4=50 cm
L=2x99/3=66 cm (99 cel mai mare nr impar de doua cifre)
P=2(L+l)=2(66+50)=232 cm
latura romb=232:4=58 cm
3. laturile triunghiului a,a+1,a+2
P=a+a+1+a+2=276
3a+3=276
3a=273, a=273:3=91 cm
4. P=2(L+l)=970 m
L+l=485
L+123=485
L=485-123=362 m
