Given that the quadrilaterals are similar, we know that:
[tex]\frac{JM}{JK}=\frac{PS}{PQ}.[/tex]Substituting the given values, we get:
[tex]\frac{5}{4.5}=\frac{3}{x}.[/tex]Solving the above equation for x, we get:
[tex]\begin{gathered} 5x=3(4.5), \\ x=\frac{3(4.5)}{5}. \end{gathered}[/tex]Simplifying the above result, we get:
[tex]x=2.7[/tex]