A long, hollow, cylindrical conductor $($inner radius $2\mathrm{.}6$ mm $,$ outer radius $7\mathrm{.}3$ mm $)$ carries a current of $29$ A distributed uniformly across its cross section. A long thin wire that is coaxial with the cylinder carries a current of $56$ A in the opposite direction. What is the magnitude of the magnetic field $($a$)1\mathrm{.}1$ mm $,($b$)2\mathrm{.}6$ mm $,$ and $($c$)8\mathrm{.}4$ mm from the central axis of the wire and cylinder?