Answer:
Step-by-step explanation:
The figures are similar, therefore they have equal ratio of corresponding sides:
So
[tex]\\ \tt\hookrightarrow \dfrac{12}{16}=\dfrac{x}{24}[/tex]
[tex]\\ \tt\hookrightarrow \dfrac{3}{4}=\dfrac{x}{24}[/tex]
[tex]\\ \tt\hookrightarrow 4x=72[/tex]
[tex]\\ \tt\hookrightarrow x=18[/tex]