[tex]ED=5.18\times10^4[/tex]
1) Since the lines AC and BD are parallel and given the measurements, we tell these triangles are similar.
2) Based on that we can write out the following ratios:
[tex]\begin{gathered} \frac{3.2\cdot \:10^3}{4.2\cdot \:10^4}=\frac{x}{6.8\cdot \:10^5} \\ \frac{x}{6.8\cdot \:10^5}=\frac{3.2\cdot \:10^3}{4.2\cdot \:10^4} \\ x=51809.52380 \\ x=5.18\cdot10^4 \end{gathered}[/tex]
Rounding off to the nearest hundredth.
