$4.)$ A $4-$m$-$diameter circular footing is supporting a water tank. The total weight of the footing, tank and its

content is $1\mathrm{.}60$ MN$.$

Given the Boussinesq's equation:

$Z=q\frac{x}{x}$I ${?}_{(}()B)$

Where $I_B=1-\frac{1}{N}$

$N=[(\frac{R}{z}{)}^2+1{]}^{\frac{3}{2}}$

a$.)$ Determine the pressure at the base of the footing

b$.)$ Using the Boussineq's equation, what is the increase in pressure at a depth of $4m$ meters below the

base footing?

c$.)$ Using the Boussineq's equation, at what depth below the base of footing is the increase in pressure

equal to $\frac{1}{6}$ the pressure at the base of footing?