1. The problem statement, all variables and given/known data ABS plastic melts (and solidifies) at 105 °C. You want to inject it into a steel mold. When the part comes out at 20°C you want it to be 7.250cm long. Edit: If this isn't clear, it wants to know how big the steel mold should be. α for ABS plastic α= 53.0x106/C°, for steel α= 11.0x106 2. Relevant equations ΔL=αL0ΔT 3. The attempt at a solution Ok so I used the equation for linear expansion and I come out with an initial length of 7.282cm. The answer I'm given is 7.276cm. I'm think this has something to do with the steel but I have no idea what. Edit: I tried a similar problem and got the right answer using the same method. I have no idea.