$[2$pt$]$

A rod is measured to be exactly $22\mathrm{.}13$ cm long using a steel ruler at a temperature of $24\mathrm{.}1C.$ Both the rod and the ruler are placed in an oven with a temperature of $309\mathrm{.}0C$ where the rod now measures $22\mathrm{.}49$ cm using the same ruler. What is the coefficient of thermal expansion for the material of which the rod is made?

Answer: $$ Submit All Answers Last Answer: $6\mathrm{.}828$E$-5$ K$^-1$

Not yet correct, tries $\frac{4}{10}$

Hint: This problem is using alpha for steel from Cutnell & Johnson, Table $12\mathrm{.}1$ Did you consider the fact that the ruler also changes its size?