Since the figures are similar, we can write the following proportion between corresponding sides:
[tex]\frac{AE}{PT}=\frac{DC}{SR}[/tex]Now, using the lengths of each side, we have:
[tex]\frac{2}{4}=\frac{5}{x}[/tex]Solving for x:
[tex]\begin{gathered} 2\cdot x=4\cdot5 \\ 2x=20 \\ x=\frac{20}{2} \\ x=10 \end{gathered}[/tex]Therefore the value of x is 10.