This is a list of topics related to pi (π), the fundamental mathematical constant. * 2π theorem * Approximations of π * Arithmetic–geometric mean * Bailey–Borwein–Plouffe formula * Basel problem * Borwein's algorithm * Buffon's needle * Cadaeic Cadenza * Chronology of computation of π * Circle * Euler's identity * Six nines in pi * Gauss–Legendre algorithm * Gaussian function * History of π * A History of Pi (book) * Indiana Pi Bill * Leibniz formula for pi * Lindemann–Weierstrass theorem (Proof that π is transcendental) * List of circle topics * List of formulae involving π * Liu Hui's π algorithm * Mathematical constant (sorted by continued fraction representation) * Mathematical constants and functions * Method of exhaust