Q$4)$ For the given figure a Square Footing to support a $40cm$ square column. The column carries a dead load $D$ of $200kN$ and a live load $L$ of $300kN.$ The allowable soil pressure capacity $150k\frac{N}{m^2}*f_c^{\text{'}}=30$MPa,$f_y=420$MPa. $.$

Assume footing effective depth $d=25cm$

a$)$ Find the $B$ dimention of footing needed

b$)$ Assume footing effective depth $d=25cm$ check if the depth is enough or not $($ consider B is $2m)($dead load $D$ of $200kN$ and a live load $L$ of $300kN.)$