El número pi: ¿para qué vale un número que en realidad es una letra?

I've been wanting to explore the curious relationship that led to the discovery of the number Pi for some time, and this video has allowed me, in addition to being able to explain its origin, to find out some very curious things about this irrational number, and the huge number of practical uses it has, to the point that our way of life would not be conceivable without this magical succession of numbers.