Answer
$25.1cm$ x $2.01m$ x $9.9m$
Work Step by Step
We know that
$L=L_{\circ}+\alpha L_{\circ}\Delta T$.........eq(1)
For thickness, we plug in the known values in eq(1) to obtain:
$H=0.254m+[1.2\times 10^{-5}(C^{\circ})^{-1}](0.254m)(20-872)^{\circ}C=0.251m=25.1cm$
For width, we plug in the known values in eq(1) to obtain:
$W=2.03m+[1.2\times 10^{-5}(C^{\circ})^{-1}](2.03m)(20-872)^{\circ}C=2.01m$
For length, we plug in the known values in eq(1) to obtain:
$L=10m+[1.2\times 10^{-5}(C^{\circ})^{-1}](10m)(20-872)^{\circ}C=9.9m$
