$($b$)$ A thin wire is formed into the shape shown. If $\backslash ($ b$=1\backslash$mathrm$\{$~m$\}\backslash ),$ determine the $\backslash ($ x $\backslash )$ and $\backslash ($ y $\backslash )$ coordinates of the centroid of the wire. $($Note that the curved part forms a circular arc and lies in a plane parallel to the $\backslash ($ x z $\backslash )$ plane.$)$