A column of a building carrying a load of 4000 kN is supported by a square footing placed at a depth of 2 m below G.L in a homogeneous layer of sand. Properties of sand are:

γ_{t soil} = 18 kN/m³, ϕ = 30° ; for ϕ = 30° ; N_C = 37.2, N_q = 22.5, N_γ = 19.7

The minimum size of footing required to resist the load with a FOS = 2.5 using Terzaghi’s formula is (in ‘m’ up to 2 decimal places)_____