"Mihai e cel mai puternic bărbat."
Translation:Michael is the strongest man.
if i understand well ( and even if I did not understand well it helped me a lot) cel - cea - cele correspond to French CELUI - CELLE - CEUX - CELLES - : for instance, this sentence which I did not understand, became very clear when I translated CEL by CELUI and I obtained the following literal translation : MIHAI est celui plus fort homme = Mihai est l'homme le plus fort, in English Mihai is the strongest man. This system works every time CEL CEA CELE appear in a sentence. I hope it will help my fellow French-speaking nationals and students.
Cel and cele are different forms of the same thing, but based on the number and genre of what they are about.
Mihai is a man, so masculine singular for which you have cel. For female singular you have cea. For plurals, you have cei for masculine and cele for feminine.
The whole expression cel mai... means the most... or in cases like this (cel mai puternic) worded a bit differently as the strongest. You can also have ele sunt cele mai mari as they are the biggest.