Răspuns :
d+d= 60 => 2d=60 => d=30
c:6=d => c:6=30 => c= 180
b+2=c => b+2=180 => b=178
2a=b => 2a=178 => a=89
c:6=d => c:6=30 => c= 180
b+2=c => b+2=180 => b=178
2a=b => 2a=178 => a=89