a) 15/20=3/4
6/8=3/4 deci formeaza proportie
b)12/16=3/4
21/28=3/4 deci formeaza proportie
c)15/25=3/5
6/9=2/3 NU formeaza proportie
d)0,3/1,5=3/15=1/5
1/5 deci formeaza proportie
e)0,2/18=2/180=1/90
1,(2)/110=(1int2/9)/110=(11/9)x(1/110)=1/90 deci formeaza proportie
f)5/7
2,5/4,5=25/45=5/9 NU formeaza proportie
g)1,8/5=18/50=9/25
0,3/4=30/40=3/4 NU formeaza proportie
h)5/9
0,(3)/2=3/9/2=3/9x1/2=3/18=1/6 NU formeaza proportie