Răspuns:
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