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## Homework Statement

A non-isotropic material is heated, fractional increase in length is different along different directions. With length l

_{1}=6.1 cm and l

_{2}=6.0 cm. In direction of l

_{1}, the coefficient expansion is [itex]\alpha[/itex]

_{1}= 10×10

^{-5}K

^{-1}and direction l

_{2}is [itex]\alpha[/itex]

_{2}= 40×10

^{-5}K

^{-1}. The plate is heated until it becomes a perfect square. What is the area of the square? (The answer is 38 cm

^{2}) I just don't know how use the equations with out a given temperature.

## Homework Equations

ΔL=[itex]\alpha[/itex]L

_{0}T

L

_{x}=L

_{x0}+L

_{x0}[itex]\alpha[/itex]ΔT

L

_{y}=L

_{y0}+L

_{y0}[itex]\alpha[/itex]ΔT

A

_{0}=L

_{x0}L

_{y0}

A=L

_{x}L

_{y}

## The Attempt at a Solution

Not sure what to do with the equations without the temperature.