We will recall that t1 ft is approximately 0.3048 m, thus:
[tex]\begin{gathered} 828m(\frac{1ft}{0.3048m})-508m(\frac{1ft}{0.3048m})=1049.868766...ft \\ \\ \approx1050ft \end{gathered}[/tex]So, it is approximately 1050 ft shorter than the Burl Khalifa.