Linear thermal expansion of steel

[honeybeau]

1. a steel plug has a diameter of 10.0 cm at 30 degrees celsius. at what temperature will the diameter be 9.986 cm?
2. a steel measuring tape is exactly 50,000 m long at 20 degrees celsius . (a) what is the length on hot summer when the temperature is 35 degrees celsius? (b) if such steel tape is used to measure a distance at 35 degrees celsius, the reading from the tape is 35.794 m. what is the actual distance?

please help me.

 

[Simon Bridge]

Welcome to PF;
Where do you need help? In general you should attempt the problem or, at least, talk about how you understand it.

Do you know what "linear thermal expansion" is?
Do you know what the "coefficient of linear expansion" for steel is?
https://en.wikipedia.org/wiki/Thermal_expansion#Coefficient_of_thermal_expansion