Aici trebuie sa folosesti reciproca teoremei lui Thales.
a) EC=AC-AE=70-30=40 cm
Verifici daca AE/EC=AD/DB
30/40=12/16 => 3/4=3/4 ADEVARAT
b) AE=AC-EC=40-24=16
Verifici daca AE/EC=AD/BD
16/24=20/36 => 0,(6)=0,(5) FALS
c) Verifici daca AC/AE=AB/AD
42/12=28/8 => 14/4=14/4 ADEVARAT