Repeat Problem 21, but now the copper washer and the steel bolt are both raised to the

Question:

Repeat Problem 21, but now the copper washer and the steel bolt are both raised to the same temperature. At what temperature will the washer fit on the bolt?
A copper washer is to be fit in place over a steel bolt. Both pieces of metal are at 20.0 °C. If the diameter of the bolt is 1.0000 cm and the inner diameter of the washer is 0.9980 cm, to what temperature must the washer be raised so it will fit over the bolt? Only the copper washer is heated.