[2] Born in Iași, he attended the Costache Negruzzi High School in his native city.
[1] Upon graduation, he became an assistant professor at the Faculty of Science of the University of Iași and began his research activity under the guidance of his advisor, Alexander Myller.
In 1932 Popa published his first papers (in differential geometry), in collaboration with Mendel Haimovici [ro].
He obtained his Ph.D. in 1934[3] with thesis Contributions to Centro-Affine Differential Geometry, in which he pursued research themes of his two mentors, Myller and Octav Mayer.
In 1936, the Romanian Academy awarded him a two-year scholarship to pursue his postdoctoral studies in Italy and Germany; during this period, he visited Enrico Bompiani at Sapienza University of Rome and Wilhelm Blaschke at the University of Hamburg.