Răspuns :
a:b=7,4
a=7b+4
a-b=124
7b+4-b=124
6b+4=124
6b=120
b=120:6
b=20
a=7*20+4
a=140+4
a=144
a=7b+4
a-b=124
7b+4-b=124
6b+4=124
6b=120
b=120:6
b=20
a=7*20+4
a=140+4
a=144
D=I.c+r
D-i=124 ,D=i+124
i+124=i.7+4
i.6=124-4
i.6=120
i=20
D=20+124=144
144=20.7+4
D-i=124 ,D=i+124
i+124=i.7+4
i.6=124-4
i.6=120
i=20
D=20+124=144
144=20.7+4