Given: ∠A ≅∠D, ∠B ≅∠E This is 2 seperate triangles
ABC is one triangle and DEF is a different triangle

We are asked to determine the value of "x". Since we have that:
[tex]\begin{gathered} ∠A≅∠D, \\ ∠B≅∠E \end{gathered}[/tex]This means that triangles ABC and DEF are similar and therefore, corresponding sides are in the same proportion as each other. Therefore, we can use the following relationship:
[tex]\frac{AB}{DE}=\frac{BC}{EF}[/tex]Substituting the values we get:
[tex]\frac{3x}{3}=\frac{30}{5}[/tex]Simplifying the fractions:
[tex]x=6[/tex]Therefore, the value of "x" is 6.