Compute the data and draw a curve of z/Q versus depth for points directly below a

Compute the data and draw a curve of σ z/Q versus depth for points directly below a point load Q. On the same plot draw curves of σ z/Q versus depth for points directly below the center of square footings with breadths of 6.5 m and 20 m, respectively, each carrying a uniformly distributed load Q. On the basis of this plot, make a statement relative to the range within which loaded areas may be considered to act as point loads. (After Taylor, 1948).?