What is the value of x?

Answer:
9
Step-by-step explanation:
The two triangles [tex]\triangle MNP\sim \triangle RST[/tex].
Therefore the corresponding sides are proportional.
[tex]\frac{|ST|}{|PN|} =\frac{|TR|}{|MP|}[/tex]
From the diagram |MP|=4, |PN|=3, |MN|=5 |ST|=x and |TR|=12.
Let us substitute the values and solve for x.
[tex]\frac{12}{4}=\frac{x}{3}[/tex]
Multiply both sides by 3 to get:
[tex]3*\frac{12}{4}=\frac{x}{3}*3[/tex]
This implies that:
[tex]9=x[/tex]
Therefore x=9