daca ducem AD_|_ BC si cu ajutorul teoremei catetei avem\
AB²=BD.BC=BD.122
AC²=DC.BC=DC.122
dar AB/AC=5/6 si AB²/AC²=25/36
AB²=AC².25/36
inlocuind
AC².25/36=BD.122⇒AC²=36.BD.122/25
AC²=DC.122
36.BD.122/25=DC.122 |:122
36BD=25DC
BD/DC=25/36
daca BD=122_DC
(122-DC)/DC=25/36
122/DC-1=25/36
122/DC=1+25/36=61/36
122/DC=61/36
DC=72 cm
BD=122-72=50 cm