1. The problem statement, all variables and given/known data A brass rod (linear expansion coef 19*10-6/°C) has a radius of 8139 cm and a copper (linear expansion coef 17*10-6/°C) sheet has a hole or radius 8139+8.86cm. What temperature change (K) is required to close the gap? 2. Relevant equations ΔL/Lo = αΔT? 3. The attempt at a solution I'm not even sure if the equation is right, so I'm really confused. Thanks for the help!