we need to find the scale factor between the triangles
6 multiplied by the factor equals 4
[tex]\begin{gathered} 6\times s=4 \\ s=\frac{4}{6} \\ s=\frac{2}{3} \end{gathered}[/tex]the scale is 2/3
now multiply 21 for the scale to find x
[tex]\begin{gathered} 21\times\frac{2}{3}=x \\ \\ x=14 \end{gathered}[/tex]the value of x is 14
