Răspuns:
a)87=a+a+1+a+2=3a+3
87-3=84 84:3=28
laturile:28;29;30
b)3BC=AB ; AC=BC+11
P=31. AB+AB/3+AB/3+11=(5AB)/3=31-11=>
5AB=20. AB=4cm
laturile:4;4/3;4/3+11=37/3
c)AB;2AB;AB+2
P=22=4AB+2=>AB=(22-2)/4=20/4=5
laturile:5 ;10;7
d)AB=3/5dinBC;AC=(AB+BC)/2
3/5BC+BC+(3/5BC-BC)/2=BC(6/5+2+3/5-1)/2=BC(6+10+3-5)10=BC14/10=7/5dinBC
P=36=7/5BC=>BC=36×5/7=180/7
AB=3/5×180/7
AC=(3/5×180/7+180/7)/2=(3×180+5×180)/70