https://en.wikipedia.org/wiki/Approximations_of_π https://en.wikipedia.org/wiki/Approximations_of_π The method of using inscribed and circumscribed n-gons conc

https://en.wikipedia.org/wiki/Approximations_of_π https://en.wikipedia.org/wiki/Approximations_of_π The method of using inscribed and circumscribed n-gons conceptually is the simplest (1), but converges very slowly. See https://arxiv.org/pdf/2008.07995.pdf https://arxiv.org/pdf/2008.07995.pdf. (1) at least to non-mathematicians. Pure mathematicians will want to prove the claims that the circumference of a circle is larger than/smaller than that of its inscribed/circumscribed polygon and that both can get arbitrarily close to it if the number of sides gets large enough.