Answer
$$T_{f}=-67^{\circ}C$$ The steel rivet must be cooled to $-67^{\circ}C$ in order to fit inside the hole.
Work Step by Step
$$\Delta l=al_{0}\Delta T$$ $$1.870m-1.872cm=(\frac{12\times10^{-6}}{^{\circ}C})(1.872cm)(T_{f}-22^{\circ}C)$$ $$T_{f}=-67.031^{\circ}C$$
