Is pi a rational number or irrrational number and why?

Answer 1

In the 18th century, Johann Heinrich Lambert was the first to prove that pi is an irrational number. However, his proof requires some pretty heavy-duty mathematics. In the 19th century Charles Hermite found a proof which is simpler but still requires requires knowledge of fairly advanced calculus. If you are up to it, then see //en.wikipedia.org/wiki/Proof_that_π_is_irrational#Hermite.27s_proof