<Dd> 1 τ = 2 π 2 − 9 9 π m α 6, (\ displaystyle (\ frac (1) (\ tau)) = 2 (\ frac (\ pi ^ (2) - 9) (9 \ pi)) m \ alpha ^ (6),) </Dd> <P> where m is the mass of the electron . </P> <P> π is present in some structural engineering formulae, such as the buckling formula derived by Euler, which gives the maximum axial load F that a long, slender column of length L, modulus of elasticity E, and area moment of inertia I can carry without buckling: </P> <Dl> <Dd> F = π 2 E I L 2 . (\ displaystyle F = (\ frac (\ pi ^ (2) EI) (L ^ (2))).) </Dd> </Dl>

Who gave the most accurate value of pi