The length of a steel beam increases by 0.78 mm when its temperature is raised from 22 degrees C to 35 degrees C. What is the length of the beam at 22 degrees C (in meters)?
I may be wrong but I think you need something else...the expansion coefficient perhaps...?
You can use the expression that describes thermal linear expansion as:
In your case:
From the litterature you have:
With the data you have and the coefficient from the table: