a)4/12=10/30=14/42=k
k=4/12 k=10/30....
k=1/3
deci sunt direct proportionate
4/12=10/3=14/42 simplificate dau fiecare 1/3
b)4·30=6·20=12·10=k
k=120
sunt iners proportionale
a) 36m--------------12 rochii
x------------------50 rochii
x=50·36/12=150 m
b)36m-----------------12r
1191m------------------x
x=12·1191/36=393 rochii