It is through one of Plato's dialogues—namely, Theaetetus—that we know that Theodorus had proven that 3 , 5 , … , 17 {\displaystyle {\sqrt {3}},{\sqrt {5}},\dots ,{\sqrt {17}}} are irrational.
Grazas a un dos diálogos de Platón, Teeteto, sabemos que Teodoro probou que 3 , 5 , … , 17 {\displaystyle \scriptstyle {\sqrt {3}},{\sqrt {5}},\dots ,{\sqrt {17}}} son irracionais.