Three vessels A, B and C of different shapes contain a water upto the same height as shown in the figure. ${\mathrm{P}}_{\mathrm{A}}, {\mathrm{P}}_{\mathrm{B}} \mathrm{and} {\mathrm{P}}_{\mathrm{C}}$ be the pressures exerted by the water at the bottom of the vessels A, B and C respectively. Then

Pressure = $\mathrm{h\rho }$g
Pressure at the bottom is independent of the area of the base of the vessel. It depends on the height of water upto which the vessel is filled with water. As in all the three vessels, level of water are the same, therefore Pressure at the bottom in all the vessels is also same. 

Hence, ${\mathrm{P}}_{\mathrm{A}} = {\mathrm{P}}_{\mathrm{B}} = {\mathrm{P}}_{\mathrm{C}}$