Question $3$: Three brass plates are brazed to a steel pipe to form the flagpole base shown. Knowing that the pipe has a wall thickness of $0\mathrm{.}6cm.$ and that each plate is $0\mathrm{.}5cm.$ thick, determine the location of the centre of gravity of the base. $($Densities: brass $8470k\frac{g}{m^3},$ steel $7750k\frac{g}{m^3}.)$

Figure $3$