ABIIdDAOB asemenea cu dDOC=>OA/OD=AB/DC=3/7=>
P=AB+BC+CD+DA=5+5+AB+DC=>AB+DC=30-10=20
DC=20-AB
3/7=AB/(20-AB)
60-3AB=7AB
AB=6=>DC=20-6=14
d-dreptunghic format cu Pitagora
5 la puterea a 2=4 la puterea a 2-h la puterea a 2=>h=3
baza mare=(14-4)=10
AC la puterea a 2= 3 la puterea a 2 + 10 la puterea a 2=9+100=109
AC= radical din 109
ctg B=ctg ( 90 + EBD)
BE=inaltime